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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      https://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.lang3;
18  
19  import java.lang.reflect.Method;
20  import java.lang.reflect.Modifier;
21  import java.util.ArrayDeque;
22  import java.util.ArrayList;
23  import java.util.Collections;
24  import java.util.Comparator;
25  import java.util.Deque;
26  import java.util.HashMap;
27  import java.util.HashSet;
28  import java.util.Iterator;
29  import java.util.LinkedHashSet;
30  import java.util.List;
31  import java.util.Map;
32  import java.util.Objects;
33  import java.util.Set;
34  import java.util.concurrent.atomic.AtomicReference;
35  import java.util.stream.Collectors;
36  
37  /**
38   * Operates on classes without using reflection.
39   *
40   * <p>
41   * This class handles invalid {@code null} inputs as best it can. Each method documents its behavior in more detail.
42   * </p>
43   *
44   * <p>
45   * The notion of a {@code canonical name} includes the human-readable name for the type, for example {@code int[]}. The
46   * non-canonical method variants work with the JVM names, such as {@code [I}.
47   * </p>
48   *
49   * @since 2.0
50   */
51  public class ClassUtils {
52  
53      /**
54       * Inclusivity literals for {@link #hierarchy(Class, Interfaces)}.
55       *
56       * @since 3.2
57       */
58      public enum Interfaces {
59  
60          /** Includes interfaces. */
61          INCLUDE,
62  
63          /** Excludes interfaces. */
64          EXCLUDE
65      }
66  
67      /**
68       * The JLS-specified maximum class name length {@value}.
69       *
70       * @see Class#forName(String, boolean, ClassLoader)
71       * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
72       * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
73       * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
74       */
75      private static final int MAX_CLASS_NAME_LENGTH = 65535;
76  
77      /**
78       * The JVM-specified {@code CONSTANT_Class_info} structure defines an array type descriptor is valid only if it represents {@value} or fewer dimensions.
79       *
80       * @see Class#forName(String, boolean, ClassLoader)
81       * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
82       * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
83       * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
84       */
85      private static final int MAX_JVM_ARRAY_DIMENSION = 255;
86  
87      /**
88       * The maximum number of array dimensions.
89       */
90      private static final int MAX_DIMENSIONS = 255;
91  
92      private static final Comparator<Class<?>> COMPARATOR = (o1, o2) -> Objects.compare(getName(o1), getName(o2), String::compareTo);
93  
94      /**
95       * The package separator character: {@code '&#x2e;' == {@value}}.
96       */
97      public static final char PACKAGE_SEPARATOR_CHAR = '.';
98  
99      /**
100      * The package separator String: {@code "&#x2e;"}.
101      */
102     public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
103 
104     /**
105      * The inner class separator character: {@code '$' == {@value}}.
106      */
107     public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
108 
109     /**
110      * The inner class separator String: {@code "$"}.
111      */
112     public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
113 
114     /**
115      * Maps names of primitives to their corresponding primitive {@link Class}es.
116      */
117     private static final Map<String, Class<?>> NAME_PRIMITIVE_MAP = new HashMap<>();
118 
119     static {
120         NAME_PRIMITIVE_MAP.put(Boolean.TYPE.getName(), Boolean.TYPE);
121         NAME_PRIMITIVE_MAP.put(Byte.TYPE.getName(), Byte.TYPE);
122         NAME_PRIMITIVE_MAP.put(Character.TYPE.getName(), Character.TYPE);
123         NAME_PRIMITIVE_MAP.put(Double.TYPE.getName(), Double.TYPE);
124         NAME_PRIMITIVE_MAP.put(Float.TYPE.getName(), Float.TYPE);
125         NAME_PRIMITIVE_MAP.put(Integer.TYPE.getName(), Integer.TYPE);
126         NAME_PRIMITIVE_MAP.put(Long.TYPE.getName(), Long.TYPE);
127         NAME_PRIMITIVE_MAP.put(Short.TYPE.getName(), Short.TYPE);
128         NAME_PRIMITIVE_MAP.put(Void.TYPE.getName(), Void.TYPE);
129     }
130 
131     /**
132      * Maps primitive {@link Class}es to their corresponding wrapper {@link Class}.
133      */
134     private static final Map<Class<?>, Class<?>> PRIMITIVE_WRAPPER_MAP = new HashMap<>();
135 
136     static {
137         PRIMITIVE_WRAPPER_MAP.put(Boolean.TYPE, Boolean.class);
138         PRIMITIVE_WRAPPER_MAP.put(Byte.TYPE, Byte.class);
139         PRIMITIVE_WRAPPER_MAP.put(Character.TYPE, Character.class);
140         PRIMITIVE_WRAPPER_MAP.put(Short.TYPE, Short.class);
141         PRIMITIVE_WRAPPER_MAP.put(Integer.TYPE, Integer.class);
142         PRIMITIVE_WRAPPER_MAP.put(Long.TYPE, Long.class);
143         PRIMITIVE_WRAPPER_MAP.put(Double.TYPE, Double.class);
144         PRIMITIVE_WRAPPER_MAP.put(Float.TYPE, Float.class);
145         PRIMITIVE_WRAPPER_MAP.put(Void.TYPE, Void.TYPE);
146     }
147 
148     /**
149      * Maps wrapper {@link Class}es to their corresponding primitive types.
150      */
151     private static final Map<Class<?>, Class<?>> WRAPPER_PRIMITIVE_MAP = new HashMap<>();
152 
153     static {
154         PRIMITIVE_WRAPPER_MAP.forEach((primitiveClass, wrapperClass) -> {
155             if (!primitiveClass.equals(wrapperClass)) {
156                 WRAPPER_PRIMITIVE_MAP.put(wrapperClass, primitiveClass);
157             }
158         });
159     }
160 
161     /**
162      * Maps a primitive class name to its corresponding abbreviation used in array class names.
163      */
164     private static final Map<String, String> ABBREVIATION_MAP;
165 
166     /**
167      * Maps an abbreviation used in array class names to corresponding primitive class name.
168      */
169     private static final Map<String, String> REVERSE_ABBREVIATION_MAP;
170 
171     /** Feed abbreviation maps. */
172     static {
173         final Map<String, String> map = new HashMap<>();
174         map.put(Integer.TYPE.getName(), "I");
175         map.put(Boolean.TYPE.getName(), "Z");
176         map.put(Float.TYPE.getName(), "F");
177         map.put(Long.TYPE.getName(), "J");
178         map.put(Short.TYPE.getName(), "S");
179         map.put(Byte.TYPE.getName(), "B");
180         map.put(Double.TYPE.getName(), "D");
181         map.put(Character.TYPE.getName(), "C");
182         ABBREVIATION_MAP = Collections.unmodifiableMap(map);
183         REVERSE_ABBREVIATION_MAP = Collections.unmodifiableMap(map.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey)));
184     }
185 
186     /**
187      * Gets the class comparator, comparing by class name.
188      *
189      * @return the class comparator.
190      * @since 3.13.0
191      */
192     public static Comparator<Class<?>> comparator() {
193         return COMPARATOR;
194     }
195 
196     /**
197      * Given a {@link List} of {@link Class} objects, this method converts them into class names.
198      *
199      * <p>
200      * A new {@link List} is returned. {@code null} objects will be copied into the returned list as {@code null}.
201      * </p>
202      *
203      * @param classes the classes to change.
204      * @return a {@link List} of class names corresponding to the Class objects, {@code null} if null input.
205      * @throws ClassCastException if {@code classes} contains a non-{@link Class} entry.
206      */
207     public static List<String> convertClassesToClassNames(final List<Class<?>> classes) {
208         return classes == null ? null : classes.stream().map(e -> getName(e, null)).collect(Collectors.toList());
209     }
210 
211     /**
212      * Given a {@link List} of class names, this method converts them into classes.
213      *
214      * <p>
215      * A new {@link List} is returned. If the class name cannot be found, {@code null} is stored in the {@link List}. If the
216      * class name in the {@link List} is {@code null}, {@code null} is stored in the output {@link List}.
217      * </p>
218      *
219      * @param classNames the classNames to change.
220      * @return a {@link List} of Class objects corresponding to the class names, {@code null} if null input.
221      * @throws ClassCastException if classNames contains a non String entry.
222      */
223     public static List<Class<?>> convertClassNamesToClasses(final List<String> classNames) {
224         if (classNames == null) {
225             return null;
226         }
227         final List<Class<?>> classes = new ArrayList<>(classNames.size());
228         classNames.forEach(className -> {
229             try {
230                 classes.add(Class.forName(className));
231             } catch (final Exception ex) {
232                 classes.add(null);
233             }
234         });
235         return classes;
236     }
237 
238     /**
239      * Gets the abbreviated name of a {@link Class}.
240      *
241      * @param cls the class to get the abbreviated name for, may be {@code null}.
242      * @param lengthHint the desired length of the abbreviated name.
243      * @return the abbreviated name or an empty string.
244      * @throws IllegalArgumentException if len &lt;= 0.
245      * @see #getAbbreviatedName(String, int)
246      * @since 3.4
247      */
248     public static String getAbbreviatedName(final Class<?> cls, final int lengthHint) {
249         if (cls == null) {
250             return StringUtils.EMPTY;
251         }
252         return getAbbreviatedName(cls.getName(), lengthHint);
253     }
254 
255     /**
256      * Gets the abbreviated class name from a {@link String}.
257      *
258      * <p>
259      * The string passed in is assumed to be a class name - it is not checked.
260      * </p>
261      *
262      * <p>
263      * The abbreviation algorithm will shorten the class name, usually without significant loss of meaning.
264      * </p>
265      *
266      * <p>
267      * The abbreviated class name will always include the complete package hierarchy. If enough space is available,
268      * rightmost sub-packages will be displayed in full length. The abbreviated package names will be shortened to a single
269      * character.
270      * </p>
271      * <p>
272      * Only package names are shortened, the class simple name remains untouched. (See examples.)
273      * </p>
274      * <p>
275      * The result will be longer than the desired length only if all the package names shortened to a single character plus
276      * the class simple name with the separating dots together are longer than the desired length. In other words, when the
277      * class name cannot be shortened to the desired length.
278      * </p>
279      * <p>
280      * If the class name can be shortened then the final length will be at most {@code lengthHint} characters.
281      * </p>
282      * <p>
283      * If the {@code lengthHint} is zero or negative then the method throws exception. If you want to achieve the shortest
284      * possible version then use {@code 1} as a {@code lengthHint}.
285      * </p>
286      *
287      * <table>
288      * <caption>Examples</caption>
289      * <tr>
290      * <td>className</td>
291      * <td>len</td>
292      * <td>return</td>
293      * </tr>
294      * <tr>
295      * <td>null</td>
296      * <td>1</td>
297      * <td>""</td>
298      * </tr>
299      * <tr>
300      * <td>"java.lang.String"</td>
301      * <td>5</td>
302      * <td>"j.l.String"</td>
303      * </tr>
304      * <tr>
305      * <td>"java.lang.String"</td>
306      * <td>15</td>
307      * <td>"j.lang.String"</td>
308      * </tr>
309      * <tr>
310      * <td>"java.lang.String"</td>
311      * <td>30</td>
312      * <td>"java.lang.String"</td>
313      * </tr>
314      * <tr>
315      * <td>"org.apache.commons.lang3.ClassUtils"</td>
316      * <td>18</td>
317      * <td>"o.a.c.l.ClassUtils"</td>
318      * </tr>
319      * </table>
320      *
321      * @param className the className to get the abbreviated name for, may be {@code null}.
322      * @param lengthHint the desired length of the abbreviated name.
323      * @return the abbreviated name or an empty string if the specified class name is {@code null} or empty string. The
324      *         abbreviated name may be longer than the desired length if it cannot be abbreviated to the desired length.
325      * @throws IllegalArgumentException if {@code len <= 0}.
326      * @since 3.4
327      */
328     public static String getAbbreviatedName(final String className, final int lengthHint) {
329         if (lengthHint <= 0) {
330             throw new IllegalArgumentException("len must be > 0");
331         }
332         if (className == null) {
333             return StringUtils.EMPTY;
334         }
335         if (className.length() <= lengthHint) {
336             return className;
337         }
338         final char[] abbreviated = className.toCharArray();
339         int target = 0;
340         int source = 0;
341         while (source < abbreviated.length) {
342             // copy the next part
343             int runAheadTarget = target;
344             while (source < abbreviated.length && abbreviated[source] != '.') {
345                 abbreviated[runAheadTarget++] = abbreviated[source++];
346             }
347 
348             ++target;
349             if (useFull(runAheadTarget, source, abbreviated.length, lengthHint) || target > runAheadTarget) {
350                 target = runAheadTarget;
351             }
352 
353             // copy the '.' unless it was the last part
354             if (source < abbreviated.length) {
355                 abbreviated[target++] = abbreviated[source++];
356             }
357         }
358         return new String(abbreviated, 0, target);
359     }
360 
361     /**
362      * Gets a {@link List} of all interfaces implemented by the given class and its superclasses.
363      *
364      * <p>
365      * The order is determined by looking through each interface in turn as declared in the source file and following its
366      * hierarchy up. Then each superclass is considered in the same way. Later duplicates are ignored, so the order is
367      * maintained.
368      * </p>
369      *
370      * @param cls the class to look up, may be {@code null}.
371      * @return the {@link List} of interfaces in order, {@code null} if null input.
372      */
373     public static List<Class<?>> getAllInterfaces(final Class<?> cls) {
374         if (cls == null) {
375             return null;
376         }
377         final LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<>();
378         getAllInterfaces(cls, interfacesFound);
379         return new ArrayList<>(interfacesFound);
380     }
381 
382     /**
383      * Gets the interfaces for the specified class.
384      *
385      * @param cls the class to look up, may be {@code null}.
386      * @param interfacesFound the {@link Set} of interfaces for the class.
387      */
388     private static void getAllInterfaces(Class<?> cls, final Set<Class<?>> interfacesFound) {
389         while (cls != null) {
390             for (final Class<?> i : cls.getInterfaces()) {
391                 if (interfacesFound.add(i)) {
392                     getAllInterfaces(i, interfacesFound);
393                 }
394             }
395             cls = cls.getSuperclass();
396         }
397     }
398 
399     /**
400      * Gets a {@link List} of superclasses for the given class.
401      *
402      * <ol>
403      * <li>The first entry is the superclass of the given class.</li>
404      * <li>The last entry is {@link Object}'s class.</li>
405      * </ol>
406      *
407      * @param cls the class to look up, may be {@code null}.
408      * @return the {@link List} of superclasses in order going up from this one {@code null} if null input.
409      */
410     public static List<Class<?>> getAllSuperclasses(final Class<?> cls) {
411         if (cls == null) {
412             return null;
413         }
414         final List<Class<?>> classes = new ArrayList<>();
415         Class<?> superclass = cls.getSuperclass();
416         while (superclass != null) {
417             classes.add(superclass);
418             superclass = superclass.getSuperclass();
419         }
420         return classes;
421     }
422 
423     /**
424      * Gets the canonical class name for a {@link Class}.
425      *
426      * @param cls the class for which to get the canonical class name; may be null.
427      * @return the canonical name of the class, or the empty String.
428      * @since 3.7
429      * @see Class#getCanonicalName()
430      */
431     public static String getCanonicalName(final Class<?> cls) {
432         return getCanonicalName(cls, StringUtils.EMPTY);
433     }
434 
435     /**
436      * Gets the canonical name for a {@link Class}.
437      *
438      * @param cls the class for which to get the canonical class name; may be null.
439      * @param valueIfNull the return value if null.
440      * @return the canonical name of the class, or {@code valueIfNull}.
441      * @since 3.7
442      * @see Class#getCanonicalName()
443      */
444     public static String getCanonicalName(final Class<?> cls, final String valueIfNull) {
445         if (cls == null) {
446             return valueIfNull;
447         }
448         final String canonicalName = cls.getCanonicalName();
449         return canonicalName == null ? valueIfNull : canonicalName;
450     }
451 
452     /**
453      * Gets the canonical name for an {@link Object}.
454      *
455      * @param object the object for which to get the canonical class name; may be null.
456      * @return the canonical name of the object, or the empty String.
457      * @since 3.7
458      * @see Class#getCanonicalName()
459      */
460     public static String getCanonicalName(final Object object) {
461         return getCanonicalName(object, StringUtils.EMPTY);
462     }
463 
464     /**
465      * Gets the canonical name for an {@link Object}.
466      *
467      * @param object the object for which to get the canonical class name; may be null.
468      * @param valueIfNull the return value if null.
469      * @return the canonical name of the object or {@code valueIfNull}.
470      * @since 3.7
471      * @see Class#getCanonicalName()
472      */
473     public static String getCanonicalName(final Object object, final String valueIfNull) {
474         if (object == null) {
475             return valueIfNull;
476         }
477         final String canonicalName = object.getClass().getCanonicalName();
478         return canonicalName == null ? valueIfNull : canonicalName;
479     }
480 
481     /**
482      * Converts a given name of class into canonical format. If name of class is not a name of array class it returns
483      * unchanged name.
484      *
485      * <p>
486      * The method does not change the {@code $} separators in case the class is inner class.
487      * </p>
488      *
489      * <p>
490      * Example:
491      * <ul>
492      * <li>{@code getCanonicalName("[I") = "int[]"}</li>
493      * <li>{@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}</li>
494      * <li>{@code getCanonicalName("java.lang.String") = "java.lang.String"}</li>
495      * </ul>
496      * </p>
497      *
498      * @param name the name of class.
499      * @return canonical form of class name.
500      * @throws IllegalArgumentException if the class name is invalid.
501      */
502     private static String getCanonicalName(final String name) {
503         String className = StringUtils.deleteWhitespace(name);
504         if (className == null) {
505             return null;
506         }
507         int dim = 0;
508         final int len = className.length();
509         while (dim < len && className.charAt(dim) == '[') {
510             dim++;
511             if (dim > MAX_DIMENSIONS) {
512                 throw new IllegalArgumentException(String.format("Maximum array dimension %d exceeded", MAX_DIMENSIONS));
513             }
514         }
515         if (dim >= len) {
516             throw new IllegalArgumentException(String.format("Invalid class name %s", name));
517         }
518         if (dim < 1) {
519             return className;
520         }
521         className = className.substring(dim);
522         if (className.startsWith("L")) {
523             if (!className.endsWith(";") || className.length() < 3) {
524                 throw new IllegalArgumentException(String.format("Invalid class name %s", name));
525             }
526             className = className.substring(1, className.length() - 1);
527         } else if (className.length() == 1) {
528             final String primitive = REVERSE_ABBREVIATION_MAP.get(className.substring(0, 1));
529             if (primitive == null) {
530                 throw new IllegalArgumentException(String.format("Invalid class name %s", name));
531             }
532             className = primitive;
533         } else {
534             throw new IllegalArgumentException(String.format("Invalid class name %s", name));
535         }
536         final StringBuilder canonicalClassNameBuffer = new StringBuilder(className.length() + dim * 2);
537         canonicalClassNameBuffer.append(className);
538         for (int i = 0; i < dim; i++) {
539             canonicalClassNameBuffer.append("[]");
540         }
541         return canonicalClassNameBuffer.toString();
542     }
543 
544     /**
545      * Gets the (initialized) class represented by {@code className} using the {@code classLoader}. This implementation
546      * supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
547      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
548      * <p>
549      * The provided class name is normalized by removing all whitespace. This is especially helpful when handling XML element values in which whitespace has not
550      * been collapsed.
551      * </p>
552      *
553      * @param classLoader the class loader to use to load the class.
554      * @param className the class name.
555      * @return the class represented by {@code className} using the {@code classLoader}.
556      * @throws NullPointerException if the className is null.
557      * @throws ClassNotFoundException if the class is not found.
558      * @throws IllegalArgumentException Thrown if the class name represents an array with more dimensions than the JVM supports, 255.
559      * @throws IllegalArgumentException Thrown if the class name length is greater than 65,535.
560      * @see Class#forName(String, boolean, ClassLoader)
561      * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
562      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
563      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
564      */
565     public static Class<?> getClass(final ClassLoader classLoader, final String className) throws ClassNotFoundException {
566         return getClass(classLoader, className, true);
567     }
568 
569     /**
570      * Gets the class represented by {@code className} using the {@code classLoader}. This implementation supports the
571      * syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}", and
572      * "{@code [Ljava.util.Map$Entry;}".
573      * <p>
574      * The provided class name is normalized by removing all whitespace. This is especially helpful when handling XML element values in which whitespace has not
575      * been collapsed.
576      * </p>
577      *
578      * @param classLoader the class loader to use to load the class.
579      * @param className the class name.
580      * @param initialize whether the class must be initialized.
581      * @return the class represented by {@code className} using the {@code classLoader}.
582      * @throws NullPointerException if the className is null.
583      * @throws ClassNotFoundException if the class is not found.
584      * @throws IllegalArgumentException Thrown if the class name represents an array with more dimensions than the JVM supports, 255.
585      * @throws IllegalArgumentException Thrown if the class name length is greater than 65,535.
586      * @see Class#forName(String, boolean, ClassLoader)
587      * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
588      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
589      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
590      */
591     public static Class<?> getClass(final ClassLoader classLoader, final String className, final boolean initialize) throws ClassNotFoundException {
592         // This method was re-written to avoid recursion and stack overflows found by fuzz testing.
593         String next = className;
594         int lastDotIndex = -1;
595         do {
596             try {
597                 final Class<?> clazz = getPrimitiveClass(next);
598                 return clazz != null ? clazz : Class.forName(toCleanName(next), initialize, classLoader);
599             } catch (final ClassNotFoundException ex) {
600                 lastDotIndex = next.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
601                 if (lastDotIndex != -1) {
602                     next = next.substring(0, lastDotIndex) + INNER_CLASS_SEPARATOR_CHAR + next.substring(lastDotIndex + 1);
603                 }
604             }
605         } while (lastDotIndex != -1);
606         throw new ClassNotFoundException(className);
607     }
608 
609     /**
610      * Gets the (initialized) class represented by {@code className} using the current thread's context class loader.
611      * This implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
612      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
613      * <p>
614      * The provided class name is normalized by removing all whitespace. This is especially helpful when handling XML element values in which whitespace has not
615      * been collapsed.
616      * </p>
617      *
618      * @param className the class name
619      * @return the class represented by {@code className} using the current thread's context class loader
620      * @throws NullPointerException if the className is null
621      * @throws ClassNotFoundException if the class is not found
622      * @throws IllegalArgumentException Thrown if the class name represents an array with more dimensions than the JVM supports, 255.
623      * @throws IllegalArgumentException Thrown if the class name length is greater than 65,535.
624      * @see Class#forName(String, boolean, ClassLoader)
625      * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
626      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
627      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
628      */
629     public static Class<?> getClass(final String className) throws ClassNotFoundException {
630         return getClass(className, true);
631     }
632 
633     /**
634      * Gets the class represented by {@code className} using the current thread's context class loader. This
635      * implementation supports the syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
636      * "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
637      * <p>
638      * The provided class name is normalized by removing all whitespace. This is especially helpful when handling XML element values in which whitespace has not
639      * been collapsed.
640      * </p>
641      *
642      * @param className the class name.
643      * @param initialize whether the class must be initialized.
644      * @return the class represented by {@code className} using the current thread's context class loader.
645      * @throws NullPointerException if the className is null.
646      * @throws ClassNotFoundException if the class is not found.
647      * @throws IllegalArgumentException Thrown if the class name represents an array with more dimensions than the JVM supports, 255.
648      * @throws IllegalArgumentException Thrown if the class name length is greater than 65,535.
649      * @see Class#forName(String, boolean, ClassLoader)
650      * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification CONSTANT_Class_info</a>
651      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
652      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
653      */
654     public static Class<?> getClass(final String className, final boolean initialize) throws ClassNotFoundException {
655         final ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
656         final ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
657         return getClass(loader, className, initialize);
658     }
659 
660     /**
661      * Delegates to {@link Class#getComponentType()} using generics.
662      *
663      * @param <T> The array class type.
664      * @param cls A class or null.
665      * @return The array component type or null.
666      * @see Class#getComponentType()
667      * @since 3.13.0
668      */
669     @SuppressWarnings("unchecked")
670     public static <T> Class<T> getComponentType(final Class<T[]> cls) {
671         return cls == null ? null : (Class<T>) cls.getComponentType();
672     }
673 
674     /**
675      * Null-safe version of {@code cls.getName()}
676      *
677      * @param cls the class for which to get the class name; may be null.
678      * @return the class name or the empty string in case the argument is {@code null}.
679      * @since 3.7
680      * @see Class#getSimpleName()
681      */
682     public static String getName(final Class<?> cls) {
683         return getName(cls, StringUtils.EMPTY);
684     }
685 
686     /**
687      * Null-safe version of {@code cls.getName()}
688      *
689      * @param cls the class for which to get the class name; may be null.
690      * @param valueIfNull the return value if the argument {@code cls} is {@code null}.
691      * @return the class name or {@code valueIfNull}
692      * @since 3.7
693      * @see Class#getName()
694      */
695     public static String getName(final Class<?> cls, final String valueIfNull) {
696         return getName(cls, valueIfNull, false);
697     }
698 
699     static String getName(final Class<?> cls, final String valueIfNull, final boolean simple) {
700         return cls == null ? valueIfNull : simple ? cls.getSimpleName() : cls.getName();
701     }
702 
703     /**
704      * Null-safe version of {@code object.getClass().getName()}
705      *
706      * @param object the object for which to get the class name; may be null.
707      * @return the class name or the empty String.
708      * @since 3.7
709      * @see Class#getSimpleName()
710      */
711     public static String getName(final Object object) {
712         return getName(object, StringUtils.EMPTY);
713     }
714 
715     /**
716      * Null-safe version of {@code object.getClass().getSimpleName()}
717      *
718      * @param object the object for which to get the class name; may be null.
719      * @param valueIfNull the value to return if {@code object} is {@code null}.
720      * @return the class name or {@code valueIfNull}.
721      * @since 3.0
722      * @see Class#getName()
723      */
724     public static String getName(final Object object, final String valueIfNull) {
725         return object == null ? valueIfNull : object.getClass().getName();
726     }
727 
728     /**
729      * Gets the package name from the canonical name of a {@link Class}.
730      *
731      * @param cls the class to get the package name for, may be {@code null}.
732      * @return the package name or an empty string.
733      * @since 2.4
734      */
735     public static String getPackageCanonicalName(final Class<?> cls) {
736         if (cls == null) {
737             return StringUtils.EMPTY;
738         }
739         return getPackageCanonicalName(cls.getName());
740     }
741 
742     /**
743      * Gets the package name from the class name of an {@link Object}.
744      *
745      * @param object the class to get the package name for, may be null.
746      * @param valueIfNull the value to return if null.
747      * @return the package name of the object, or the null value.
748      * @since 2.4
749      */
750     public static String getPackageCanonicalName(final Object object, final String valueIfNull) {
751         if (object == null) {
752             return valueIfNull;
753         }
754         return getPackageCanonicalName(object.getClass().getName());
755     }
756 
757     /**
758      * Gets the package name from the class name.
759      *
760      * <p>
761      * The string passed in is assumed to be a class name - it is not checked.
762      * </p>
763      * <p>
764      * If the class is in the default package, return an empty string.
765      * </p>
766      *
767      * @param name the name to get the package name for, may be {@code null}.
768      * @return the package name or an empty string.
769      * @since 2.4
770      */
771     public static String getPackageCanonicalName(final String name) {
772         return getPackageName(getCanonicalName(name));
773     }
774 
775     /**
776      * Gets the package name of a {@link Class}.
777      *
778      * @param cls the class to get the package name for, may be {@code null}.
779      * @return the package name or an empty string
780      */
781     public static String getPackageName(final Class<?> cls) {
782         if (cls == null) {
783             return StringUtils.EMPTY;
784         }
785         return getPackageName(cls.getName());
786     }
787 
788     /**
789      * Gets the package name of an {@link Object}.
790      *
791      * @param object the class to get the package name for, may be null.
792      * @param valueIfNull the value to return if null.
793      * @return the package name of the object, or the null value.
794      */
795     public static String getPackageName(final Object object, final String valueIfNull) {
796         if (object == null) {
797             return valueIfNull;
798         }
799         return getPackageName(object.getClass());
800     }
801 
802     /**
803      * Gets the package name from a {@link String}.
804      *
805      * <p>
806      * The string passed in is assumed to be a class name.
807      * </p>
808      * <p>
809      * If the class is unpackaged, return an empty string.
810      * </p>
811      *
812      * @param className the className to get the package name for, may be {@code null}.
813      * @return the package name or an empty string.
814      */
815     public static String getPackageName(String className) {
816         if (StringUtils.isEmpty(className)) {
817             return StringUtils.EMPTY;
818         }
819         int i = 0;
820         // Strip array encoding
821         while (className.charAt(i) == '[') {
822             i++;
823         }
824         className = className.substring(i);
825         // Strip Object type encoding
826         if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
827             className = className.substring(1);
828         }
829         i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
830         if (i == -1) {
831             return StringUtils.EMPTY;
832         }
833         return className.substring(0, i);
834     }
835 
836     /**
837      * Gets the primitive class for the given class name, for example "byte".
838      *
839      * @param className the primitive class for the given class name.
840      * @return the primitive class.
841      */
842     static Class<?> getPrimitiveClass(final String className) {
843         return NAME_PRIMITIVE_MAP.get(className);
844     }
845 
846     /**
847      * Gets the desired Method much like {@code Class.getMethod}, however it ensures that the returned Method is from a
848      * public class or interface and not from an anonymous inner class. This means that the Method is invokable and doesn't
849      * fall foul of Java bug (<a href="https://bugs.java.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
850      *
851      * <pre>
852      *  {@code Set set = Collections.unmodifiableSet(...);
853      *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
854      *  Object result = method.invoke(set, new Object[]);}
855      * </pre>
856      *
857      * @param cls the class to check, not null.
858      * @param methodName the name of the method.
859      * @param parameterTypes the list of parameters.
860      * @return the method.
861      * @throws NullPointerException if the class is null.
862      * @throws SecurityException if a security violation occurred.
863      * @throws NoSuchMethodException if the method is not found in the given class or if the method doesn't conform with the
864      *         requirements.
865      */
866     public static Method getPublicMethod(final Class<?> cls, final String methodName, final Class<?>... parameterTypes) throws NoSuchMethodException {
867         final Method declaredMethod = cls.getMethod(methodName, parameterTypes);
868         if (isPublic(declaredMethod.getDeclaringClass())) {
869             return declaredMethod;
870         }
871         final List<Class<?>> candidateClasses = new ArrayList<>(getAllInterfaces(cls));
872         candidateClasses.addAll(getAllSuperclasses(cls));
873         for (final Class<?> candidateClass : candidateClasses) {
874             if (!isPublic(candidateClass)) {
875                 continue;
876             }
877             final Method candidateMethod;
878             try {
879                 candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
880             } catch (final NoSuchMethodException ex) {
881                 continue;
882             }
883             if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
884                 return candidateMethod;
885             }
886         }
887         throw new NoSuchMethodException("Can't find a public method for " + methodName + " " + ArrayUtils.toString(parameterTypes));
888     }
889 
890     /**
891      * Gets the canonical name minus the package name from a {@link Class}.
892      *
893      * @param cls the class for which to get the short canonical class name; may be null.
894      * @return the canonical name without the package name or an empty string.
895      * @since 2.4
896      * @see Class#getCanonicalName()
897      */
898     public static String getShortCanonicalName(final Class<?> cls) {
899         return cls == null ? StringUtils.EMPTY : getShortCanonicalName(cls.getCanonicalName());
900     }
901 
902     /**
903      * Gets the canonical name minus the package name for an {@link Object}.
904      *
905      * @param object the class to get the short name for, may be null.
906      * @param valueIfNull the value to return if null.
907      * @return the canonical name of the object without the package name, or the null value.
908      * @since 2.4
909      * @see Class#getCanonicalName()
910      */
911     public static String getShortCanonicalName(final Object object, final String valueIfNull) {
912         return object == null ? valueIfNull : getShortCanonicalName(object.getClass());
913     }
914 
915     /**
916      * Gets the canonical name minus the package name from a String.
917      *
918      * <p>
919      * The string passed in is assumed to be a class name - it is not checked.
920      * </p>
921      *
922      * <p>
923      * Note that this method is mainly designed to handle the arrays and primitives properly. If the class is an inner class
924      * then the result value will not contain the outer classes. This way the behavior of this method is different from
925      * {@link #getShortClassName(String)}. The argument in that case is class name and not canonical name and the return
926      * value retains the outer classes.
927      * </p>
928      *
929      * <p>
930      * Note that there is no way to reliably identify the part of the string representing the package hierarchy and the part
931      * that is the outer class or classes in case of an inner class. Trying to find the class would require reflective call
932      * and the class itself may not even be on the class path. Relying on the fact that class names start with capital
933      * letter and packages with lower case is heuristic.
934      * </p>
935      *
936      * <p>
937      * It is recommended to use {@link #getShortClassName(String)} for cases when the class is an inner class and use this
938      * method for cases it is designed for.
939      * </p>
940      *
941      * <table>
942      * <caption>Examples</caption>
943      * <tr>
944      * <td>return value</td>
945      * <td>input</td>
946      * </tr>
947      * <tr>
948      * <td>{@code ""}</td>
949      * <td>{@code (String) null}</td>
950      * </tr>
951      * <tr>
952      * <td>{@code "Map.Entry"}</td>
953      * <td>{@code java.util.Map.Entry.class.getName()}</td>
954      * </tr>
955      * <tr>
956      * <td>{@code "Entry"}</td>
957      * <td>{@code java.util.Map.Entry.class.getCanonicalName()}</td>
958      * </tr>
959      * <tr>
960      * <td>{@code "ClassUtils"}</td>
961      * <td>{@code "org.apache.commons.lang3.ClassUtils"}</td>
962      * </tr>
963      * <tr>
964      * <td>{@code "ClassUtils[]"}</td>
965      * <td>{@code "[Lorg.apache.commons.lang3.ClassUtils;"}</td>
966      * </tr>
967      * <tr>
968      * <td>{@code "ClassUtils[][]"}</td>
969      * <td>{@code "[[Lorg.apache.commons.lang3.ClassUtils;"}</td>
970      * </tr>
971      * <tr>
972      * <td>{@code "ClassUtils[]"}</td>
973      * <td>{@code "org.apache.commons.lang3.ClassUtils[]"}</td>
974      * </tr>
975      * <tr>
976      * <td>{@code "ClassUtils[][]"}</td>
977      * <td>{@code "org.apache.commons.lang3.ClassUtils[][]"}</td>
978      * </tr>
979      * <tr>
980      * <td>{@code "int[]"}</td>
981      * <td>{@code "[I"}</td>
982      * </tr>
983      * <tr>
984      * <td>{@code "int[]"}</td>
985      * <td>{@code int[].class.getCanonicalName()}</td>
986      * </tr>
987      * <tr>
988      * <td>{@code "int[]"}</td>
989      * <td>{@code int[].class.getName()}</td>
990      * </tr>
991      * <tr>
992      * <td>{@code "int[][]"}</td>
993      * <td>{@code "[[I"}</td>
994      * </tr>
995      * <tr>
996      * <td>{@code "int[]"}</td>
997      * <td>{@code "int[]"}</td>
998      * </tr>
999      * <tr>
1000      * <td>{@code "int[][]"}</td>
1001      * <td>{@code "int[][]"}</td>
1002      * </tr>
1003      * </table>
1004      *
1005      * @param canonicalName the class name to get the short name for.
1006      * @return the canonical name of the class without the package name or an empty string.
1007      * @since 2.4
1008      */
1009     public static String getShortCanonicalName(final String canonicalName) {
1010         return getShortClassName(getCanonicalName(canonicalName));
1011     }
1012 
1013     /**
1014      * Gets the class name minus the package name from a {@link Class}.
1015      *
1016      * @param cls the class to get the short name for.
1017      * @return the class name without the package name or an empty string. If the class is an inner class then the returned
1018      *         value will contain the outer class or classes separated with {@code .} (dot) character.
1019      */
1020     public static String getShortClassName(final Class<?> cls) {
1021         if (cls == null) {
1022             return StringUtils.EMPTY;
1023         }
1024         int dim = 0;
1025         Class<?> c = cls;
1026         while (c.isArray()) {
1027             dim++;
1028             c = c.getComponentType();
1029         }
1030         final String base;
1031         // Preserve legacy behavior for anonymous/local classes (keeps compiler ordinals: $13, $10Named, etc.)
1032         if (c.isAnonymousClass() || c.isLocalClass()) {
1033             base = getShortClassName(c.getName());
1034         } else {
1035             final Deque<String> parts = new ArrayDeque<>();
1036             Class<?> x = c;
1037             while (x != null) {
1038                 parts.push(x.getSimpleName());
1039                 x = x.getDeclaringClass();
1040             }
1041             base = String.join(".", parts);
1042         }
1043         return base + StringUtils.repeat("[]", dim);
1044     }
1045 
1046     /**
1047      * Gets the class name of the {@code object} without the package name or names.
1048      *
1049      * @param object the class to get the short name for, may be {@code null}.
1050      * @param valueIfNull the value to return if the object is {@code null}.
1051      * @return the class name of the object without the package name, or {@code valueIfNull} if the argument {@code object}
1052      *         is {@code null}.
1053      */
1054     public static String getShortClassName(final Object object, final String valueIfNull) {
1055         if (object == null) {
1056             return valueIfNull;
1057         }
1058         return getShortClassName(object.getClass());
1059     }
1060 
1061     /**
1062      * Gets the class name minus the package name from a String.
1063      *
1064      * <p>
1065      * The string passed in is assumed to be a class name - it is not checked. The string has to be formatted the way as the
1066      * JDK method {@code Class.getName()} returns it, and not the usual way as we write it, for example in import
1067      * statements, or as it is formatted by {@code Class.getCanonicalName()}.
1068      * </p>
1069      *
1070      * <p>
1071      * The difference is significant only in case of classes that are inner classes of some other classes. In this case
1072      * the separator between the outer and inner class (possibly on multiple hierarchy level) has to be {@code $} (dollar
1073      * sign) and not {@code .} (dot), as it is returned by {@code Class.getName()}
1074      * </p>
1075      *
1076      * <p>
1077      * Note that this method is called from the {@link #getShortClassName(Class)} method using the string returned by
1078      * {@code Class.getName()}.
1079      * </p>
1080      *
1081      * <p>
1082      * Note that this method differs from {@link #getSimpleName(Class)} in that this will return, for example
1083      * {@code "Map.Entry"} whilst the {@link Class} variant will simply return {@code "Entry"}. In this example
1084      * the argument {@code className} is the string {@code java.util.Map$Entry} (note the {@code $} sign).
1085      * </p>
1086      *
1087      * @param className the className to get the short name for. It has to be formatted as returned by
1088      *        {@code Class.getName()} and not {@code Class.getCanonicalName()}.
1089      * @return the class name of the class without the package name or an empty string. If the class is an inner class then
1090      *         value contains the outer class or classes and the separator is replaced to be {@code .} (dot) character.
1091      */
1092     public static String getShortClassName(String className) {
1093         if (StringUtils.isEmpty(className)) {
1094             return StringUtils.EMPTY;
1095         }
1096         final StringBuilder arrayPrefix = new StringBuilder();
1097         // Handle array encoding
1098         if (className.startsWith("[")) {
1099             while (className.charAt(0) == '[') {
1100                 className = className.substring(1);
1101                 arrayPrefix.append("[]");
1102             }
1103             // Strip Object type encoding
1104             if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
1105                 className = className.substring(1, className.length() - 1);
1106             }
1107             if (REVERSE_ABBREVIATION_MAP.containsKey(className)) {
1108                 className = REVERSE_ABBREVIATION_MAP.get(className);
1109             }
1110         }
1111         final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
1112         final int innerIdx = className.indexOf(INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
1113         String out = className.substring(lastDotIdx + 1);
1114         if (innerIdx != -1) {
1115             out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
1116         }
1117         return out + arrayPrefix;
1118     }
1119 
1120     /**
1121      * Null-safe version of {@code cls.getSimpleName()}
1122      *
1123      * @param cls the class for which to get the simple name; may be null.
1124      * @return the simple class name or the empty string in case the argument is {@code null}.
1125      * @since 3.0
1126      * @see Class#getSimpleName()
1127      */
1128     public static String getSimpleName(final Class<?> cls) {
1129         return getSimpleName(cls, StringUtils.EMPTY);
1130     }
1131 
1132     /**
1133      * Null-safe version of {@code cls.getSimpleName()}
1134      *
1135      * @param cls the class for which to get the simple name; may be null.
1136      * @param valueIfNull the value to return if null.
1137      * @return the simple class name or {@code valueIfNull} if the argument {@code cls} is {@code null}.
1138      * @since 3.0
1139      * @see Class#getSimpleName()
1140      */
1141     public static String getSimpleName(final Class<?> cls, final String valueIfNull) {
1142         return cls == null ? valueIfNull : cls.getSimpleName();
1143     }
1144 
1145     /**
1146      * Null-safe version of {@code object.getClass().getSimpleName()}
1147      *
1148      * <p>
1149      * It is to note that this method is overloaded and in case the argument {@code object} is a {@link Class} object then
1150      * the {@link #getSimpleName(Class)} will be invoked. If this is a significant possibility then the caller should check
1151      * this case and call {@code
1152      * getSimpleName(Class.class)} or just simply use the string literal {@code "Class"}, which is the result of the method
1153      * in that case.
1154      * </p>
1155      *
1156      * @param object the object for which to get the simple class name; may be null.
1157      * @return the simple class name or the empty string in case the argument is {@code null}.
1158      * @since 3.7
1159      * @see Class#getSimpleName()
1160      */
1161     public static String getSimpleName(final Object object) {
1162         return getSimpleName(object, StringUtils.EMPTY);
1163     }
1164 
1165     /**
1166      * Null-safe version of {@code object.getClass().getSimpleName()}
1167      *
1168      * @param object the object for which to get the simple class name; may be null.
1169      * @param valueIfNull the value to return if {@code object} is {@code null}.
1170      * @return the simple class name or {@code valueIfNull} if the argument {@code object} is {@code null}.
1171      * @since 3.0
1172      * @see Class#getSimpleName()
1173      */
1174     public static String getSimpleName(final Object object, final String valueIfNull) {
1175         return object == null ? valueIfNull : object.getClass().getSimpleName();
1176     }
1177 
1178     /**
1179      * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
1180      * excluding interfaces.
1181      *
1182      * @param type the type to get the class hierarchy from.
1183      * @return Iterable an Iterable over the class hierarchy of the given class.
1184      * @since 3.2
1185      */
1186     public static Iterable<Class<?>> hierarchy(final Class<?> type) {
1187         return hierarchy(type, Interfaces.EXCLUDE);
1188     }
1189 
1190     /**
1191      * Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
1192      *
1193      * @param type the type to get the class hierarchy from.
1194      * @param interfacesBehavior switch indicating whether to include or exclude interfaces.
1195      * @return Iterable an Iterable over the class hierarchy of the given class.
1196      * @since 3.2
1197      */
1198     public static Iterable<Class<?>> hierarchy(final Class<?> type, final Interfaces interfacesBehavior) {
1199         final Iterable<Class<?>> classes = () -> {
1200             final AtomicReference<Class<?>> next = new AtomicReference<>(type);
1201             return new Iterator<Class<?>>() {
1202 
1203                 @Override
1204                 public boolean hasNext() {
1205                     return next.get() != null;
1206                 }
1207 
1208                 @Override
1209                 public Class<?> next() {
1210                     return next.getAndUpdate(Class::getSuperclass);
1211                 }
1212 
1213                 @Override
1214                 public void remove() {
1215                     throw new UnsupportedOperationException();
1216                 }
1217 
1218             };
1219         };
1220         if (interfacesBehavior != Interfaces.INCLUDE) {
1221             return classes;
1222         }
1223         return () -> {
1224             final Set<Class<?>> seenInterfaces = new HashSet<>();
1225             final Iterator<Class<?>> wrapped = classes.iterator();
1226 
1227             return new Iterator<Class<?>>() {
1228                 Iterator<Class<?>> interfaces = Collections.emptyIterator();
1229 
1230                 @Override
1231                 public boolean hasNext() {
1232                     return interfaces.hasNext() || wrapped.hasNext();
1233                 }
1234 
1235                 @Override
1236                 public Class<?> next() {
1237                     if (interfaces.hasNext()) {
1238                         final Class<?> nextInterface = interfaces.next();
1239                         seenInterfaces.add(nextInterface);
1240                         return nextInterface;
1241                     }
1242                     final Class<?> nextSuperclass = wrapped.next();
1243                     final Set<Class<?>> currentInterfaces = new LinkedHashSet<>();
1244                     walkInterfaces(currentInterfaces, nextSuperclass);
1245                     interfaces = currentInterfaces.iterator();
1246                     return nextSuperclass;
1247                 }
1248 
1249                 @Override
1250                 public void remove() {
1251                     throw new UnsupportedOperationException();
1252                 }
1253 
1254                 private void walkInterfaces(final Set<Class<?>> addTo, final Class<?> c) {
1255                     for (final Class<?> iface : c.getInterfaces()) {
1256                         if (!seenInterfaces.contains(iface)) {
1257                             addTo.add(iface);
1258                         }
1259                         walkInterfaces(addTo, iface);
1260                     }
1261                 }
1262 
1263             };
1264         };
1265     }
1266 
1267     /**
1268      * Tests whether one {@link Class} can be assigned to a variable of another {@link Class}.
1269      *
1270      * <p>
1271      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1272      * primitive classes and {@code null}s.
1273      * </p>
1274      *
1275      * <p>
1276      * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1277      * for these cases.
1278      * </p>
1279      *
1280      * <p>
1281      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1282      * and the toClass is non-primitive.
1283      * </p>
1284      *
1285      * <p>
1286      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1287      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1288      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1289      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1290      * </p>
1291      *
1292      * <p>
1293      * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1294      * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1295      * VMs running Java versions &gt; 1.5.
1296      * </p>
1297      *
1298      * @param cls the Class to check, may be null.
1299      * @param toClass the Class to try to assign into, returns false if null.
1300      * @return {@code true} if assignment possible.
1301      */
1302     public static boolean isAssignable(final Class<?> cls, final Class<?> toClass) {
1303         return isAssignable(cls, toClass, true);
1304     }
1305 
1306     /**
1307      * Tests whether one {@link Class} can be assigned to a variable of another {@link Class}.
1308      *
1309      * <p>
1310      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1311      * primitive classes and {@code null}s.
1312      * </p>
1313      *
1314      * <p>
1315      * Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result
1316      * for these cases.
1317      * </p>
1318      *
1319      * <p>
1320      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1321      * and the toClass is non-primitive.
1322      * </p>
1323      *
1324      * <p>
1325      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1326      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1327      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1328      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1329      * </p>
1330      *
1331      * @param cls the Class to check, may be null.
1332      * @param toClass the Class to try to assign into, returns false if null.
1333      * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers.
1334      * @return {@code true} if assignment possible.
1335      */
1336     public static boolean isAssignable(Class<?> cls, final Class<?> toClass, final boolean autoboxing) {
1337         if (toClass == null) {
1338             return false;
1339         }
1340         // have to check for null, as isAssignableFrom doesn't
1341         if (cls == null) {
1342             return !toClass.isPrimitive();
1343         }
1344         // autoboxing:
1345         if (autoboxing) {
1346             if (cls.isPrimitive() && !toClass.isPrimitive()) {
1347                 cls = primitiveToWrapper(cls);
1348                 if (cls == null) {
1349                     return false;
1350                 }
1351             }
1352             if (toClass.isPrimitive() && !cls.isPrimitive()) {
1353                 cls = wrapperToPrimitive(cls);
1354                 if (cls == null) {
1355                     return false;
1356                 }
1357             }
1358         }
1359         if (cls.equals(toClass)) {
1360             return true;
1361         }
1362         if (cls.isPrimitive()) {
1363             if (!toClass.isPrimitive()) {
1364                 return false;
1365             }
1366             if (Integer.TYPE.equals(cls)) {
1367                 return Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1368             }
1369             if (Long.TYPE.equals(cls)) {
1370                 return Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1371             }
1372             if (Boolean.TYPE.equals(cls)) {
1373                 return false;
1374             }
1375             if (Double.TYPE.equals(cls)) {
1376                 return false;
1377             }
1378             if (Float.TYPE.equals(cls)) {
1379                 return Double.TYPE.equals(toClass);
1380             }
1381             if (Character.TYPE.equals(cls)  || Short.TYPE.equals(cls)) {
1382                 return Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
1383             }
1384             if (Byte.TYPE.equals(cls)) {
1385                 return Short.TYPE.equals(toClass) || Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass)
1386                     || Double.TYPE.equals(toClass);
1387             }
1388             // should never get here
1389             return false;
1390         }
1391         return toClass.isAssignableFrom(cls);
1392     }
1393 
1394     /**
1395      * Tests whether an array of Classes can be assigned to another array of Classes.
1396      *
1397      * <p>
1398      * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1399      * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1400      * types (the second parameter).
1401      * </p>
1402      *
1403      * <p>
1404      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1405      * primitive classes and {@code null}s.
1406      * </p>
1407      *
1408      * <p>
1409      * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1410      * returns the correct result for these cases.
1411      * </p>
1412      *
1413      * <p>
1414      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1415      * and the toClass is non-primitive.
1416      * </p>
1417      *
1418      * <p>
1419      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1420      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1421      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1422      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1423      * </p>
1424      *
1425      * <p>
1426      * <strong>Since Lang 3.0,</strong> this method will default behavior for calculating assignability between primitive
1427      * and wrapper types <em>corresponding to the running Java version</em>; i.e. autoboxing will be the default behavior in
1428      * VMs running Java versions &gt; 1.5.
1429      * </p>
1430      *
1431      * @param classArray the array of Classes to check, may be {@code null}.
1432      * @param toClassArray the array of Classes to try to assign into, may be {@code null}.
1433      * @return {@code true} if assignment possible.
1434      */
1435     public static boolean isAssignable(final Class<?>[] classArray, final Class<?>... toClassArray) {
1436         return isAssignable(classArray, toClassArray, true);
1437     }
1438 
1439     /**
1440      * Tests whether an array of Classes can be assigned to another array of Classes.
1441      *
1442      * <p>
1443      * This method calls {@link #isAssignable(Class, Class) isAssignable} for each Class pair in the input arrays. It can be
1444      * used to check if a set of arguments (the first parameter) are suitably compatible with a set of method parameter
1445      * types (the second parameter).
1446      * </p>
1447      *
1448      * <p>
1449      * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this method takes into account widenings of
1450      * primitive classes and {@code null}s.
1451      * </p>
1452      *
1453      * <p>
1454      * Primitive widenings allow an int to be assigned to a {@code long}, {@code float} or {@code double}. This method
1455      * returns the correct result for these cases.
1456      * </p>
1457      *
1458      * <p>
1459      * {@code null} may be assigned to any reference type. This method will return {@code true} if {@code null} is passed in
1460      * and the toClass is non-primitive.
1461      * </p>
1462      *
1463      * <p>
1464      * Specifically, this method tests whether the type represented by the specified {@link Class} parameter can be
1465      * converted to the type represented by this {@link Class} object via an identity conversion widening primitive or
1466      * widening reference conversion. See <em><a href="https://docs.oracle.com/javase/specs/">The Java Language
1467      * Specification</a></em>, sections 5.1.1, 5.1.2 and 5.1.4 for details.
1468      * </p>
1469      *
1470      * @param classArray the array of Classes to check, may be {@code null}
1471      * @param toClassArray the array of Classes to try to assign into, may be {@code null}
1472      * @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
1473      * @return {@code true} if assignment possible
1474      */
1475     public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, final boolean autoboxing) {
1476         if (!ArrayUtils.isSameLength(classArray, toClassArray)) {
1477             return false;
1478         }
1479         classArray = ArrayUtils.nullToEmpty(classArray);
1480         toClassArray = ArrayUtils.nullToEmpty(toClassArray);
1481         for (int i = 0; i < classArray.length; i++) {
1482             if (!isAssignable(classArray[i], toClassArray[i], autoboxing)) {
1483                 return false;
1484             }
1485         }
1486         return true;
1487     }
1488 
1489     /**
1490      * Tests whether the specified class an inner class or static nested class.
1491      *
1492      * @param cls the class to check, may be null.
1493      * @return {@code true} if the class is an inner or static nested class, false if not or {@code null}.
1494      */
1495     public static boolean isInnerClass(final Class<?> cls) {
1496         return cls != null && cls.getEnclosingClass() != null;
1497     }
1498 
1499     /**
1500      * Tests whether the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1501      * {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1502      *
1503      * @param type The class to query or null.
1504      * @return true if the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte},
1505      *         {@link Character}, {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1506      * @since 3.1
1507      */
1508     public static boolean isPrimitiveOrWrapper(final Class<?> type) {
1509         return type != null && type.isPrimitive() || isPrimitiveWrapper(type);
1510     }
1511 
1512     /**
1513      * Tests whether the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1514      * {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1515      *
1516      * @param type The class to query or null.
1517      * @return true if the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
1518      *         {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
1519      * @since 3.1
1520      */
1521     public static boolean isPrimitiveWrapper(final Class<?> type) {
1522         return WRAPPER_PRIMITIVE_MAP.containsKey(type);
1523     }
1524 
1525     /**
1526      * Tests whether a {@link Class} is public.
1527      *
1528      * @param cls Class to test.
1529      * @return {@code true} if {@code cls} is public.
1530      * @since 3.13.0
1531      */
1532     public static boolean isPublic(final Class<?> cls) {
1533         return Modifier.isPublic(cls.getModifiers());
1534     }
1535 
1536     /**
1537      * Converts the specified array of primitive Class objects to an array of its corresponding wrapper Class objects.
1538      *
1539      * @param classes the class array to convert, may be null or empty.
1540      * @return an array which contains for each given class, the wrapper class or the original class if class is not a primitive. {@code null} if null input.
1541      *         Empty array if an empty array passed in.
1542      * @since 2.1
1543      */
1544     public static Class<?>[] primitivesToWrappers(final Class<?>... classes) {
1545         if (classes == null) {
1546             return null;
1547         }
1548         if (classes.length == 0) {
1549             return classes;
1550         }
1551         return ArrayUtils.setAll(new Class[classes.length], i -> primitiveToWrapper(classes[i]));
1552     }
1553 
1554     /**
1555      * Converts the specified primitive Class object to its corresponding wrapper Class object.
1556      *
1557      * <p>
1558      * NOTE: From v2.2, this method handles {@code Void.TYPE}, returning {@code Void.TYPE}.
1559      * </p>
1560      *
1561      * @param cls the class to convert, may be null.
1562      * @return the wrapper class for {@code cls} or {@code cls} if {@code cls} is not a primitive. {@code null} if null input.
1563      * @since 2.1
1564      */
1565     public static Class<?> primitiveToWrapper(final Class<?> cls) {
1566         return cls != null && cls.isPrimitive() ? PRIMITIVE_WRAPPER_MAP.get(cls) : cls;
1567     }
1568 
1569     /**
1570      * Converts an array of {@link Object} in to an array of {@link Class} objects. If any of these objects is null, a null element will be inserted into the
1571      * array.
1572      *
1573      * <p>
1574      * This method returns {@code null} for a {@code null} input array.
1575      * </p>
1576      *
1577      * @param array an {@link Object} array.
1578      * @return a {@link Class} array, {@code null} if null array input.
1579      * @since 2.4
1580      */
1581     public static Class<?>[] toClass(final Object... array) {
1582         if (array == null) {
1583             return null;
1584         }
1585         if (array.length == 0) {
1586             return ArrayUtils.EMPTY_CLASS_ARRAY;
1587         }
1588         return ArrayUtils.setAll(new Class[array.length], i -> array[i] == null ? null : array[i].getClass());
1589     }
1590 
1591     /**
1592      * Converts and cleans up a class name to a JLS style class name.
1593      * <p>
1594      * The provided class name is normalized by removing all whitespace. This is especially helpful when handling XML element values in which whitespace has not
1595      * been collapsed.
1596      * </p>
1597      *
1598      * @param className the class name.
1599      * @return the converted name.
1600      * @throws NullPointerException     if the className is null.
1601      * @throws IllegalArgumentException Thrown if the class name represents an array with more dimensions than the JVM supports, 255.
1602      * @throws IllegalArgumentException Thrown if the class name length is greater than 65,535.
1603      * @see <a href="https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-4.4.1">JVM: Array dimension limits in JVM Specification
1604      *      CONSTANT_Class_info</a>
1605      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-6.html#jls-6.7">JLS: Fully Qualified Names and Canonical Names</a>
1606      * @see <a href="https://docs.oracle.com/javase/specs/jls/se25/html/jls-13.html#jls-13.1">JLS: The Form of a Binary</a>
1607      */
1608     private static String toCleanName(final String className) {
1609         String canonicalName = StringUtils.deleteWhitespace(className);
1610         Objects.requireNonNull(canonicalName, "className");
1611         if (canonicalName.isEmpty()) {
1612             throw new IllegalArgumentException("Class name is empty");
1613         }
1614         final String encodedArrayOpen = "[";
1615         final String encodedClassNameStart = "L";
1616         final String encodedClassNameEnd = ";";
1617         final boolean encodedName = canonicalName.startsWith(encodedArrayOpen) && canonicalName.endsWith(encodedClassNameEnd);
1618         if (encodedName) {
1619             final int arrIdx = canonicalName.indexOf(encodedClassNameStart);
1620             if (arrIdx > MAX_JVM_ARRAY_DIMENSION) {
1621                 throw new IllegalArgumentException("Array dimension greater than JVM specification maximum of 255.");
1622             }
1623             if (arrIdx < 0) {
1624                 throw new IllegalArgumentException("Expected 'L' after '[' for an array style string.");
1625             }
1626             final int cnLen = canonicalName.length() - (arrIdx + 2); // account for the ending ';'
1627             if (cnLen > MAX_CLASS_NAME_LENGTH) {
1628                 throw new IllegalArgumentException(String.format("Class name greater than maxium length %,d", MAX_CLASS_NAME_LENGTH));
1629             }
1630         }
1631         final String arrayMarker = "[]";
1632         final int arrIdx = canonicalName.indexOf(arrayMarker);
1633         // The class name length without array markers.
1634         final int cnLen = arrIdx > 0 ? arrIdx : canonicalName.length();
1635         if (cnLen > MAX_CLASS_NAME_LENGTH && !encodedName) {
1636             throw new IllegalArgumentException(String.format("Class name greater than maxium length %,d", MAX_CLASS_NAME_LENGTH));
1637         }
1638         if (canonicalName.endsWith(arrayMarker)) {
1639             final int dims =  (canonicalName.length() - arrIdx) / 2;
1640             if (dims > MAX_JVM_ARRAY_DIMENSION) {
1641                 throw new IllegalArgumentException("Array dimension greater than JVM specification maximum of 255.");
1642             }
1643             final StringBuilder classNameBuffer = new StringBuilder(StringUtils.repeat(encodedArrayOpen, dims));
1644             canonicalName = canonicalName.substring(0, arrIdx);
1645             final String abbreviation = ABBREVIATION_MAP.get(canonicalName);
1646             if (abbreviation != null) {
1647                 classNameBuffer.append(abbreviation);
1648             } else {
1649                 classNameBuffer.append(encodedClassNameStart).append(canonicalName).append(encodedClassNameEnd);
1650             }
1651             canonicalName = classNameBuffer.toString();
1652         }
1653         return canonicalName;
1654     }
1655 
1656     /**
1657      * Decides if the part that was just copied to its destination location in the work array can be kept as it was copied
1658      * or must be abbreviated. It must be kept when the part is the last one, which is the simple name of the class. In this
1659      * case the {@code source} index, from where the characters are copied points one position after the last character,
1660      * a.k.a. {@code source ==
1661      * originalLength}
1662      *
1663      * <p>
1664      * If the part is not the last one then it can be kept unabridged if the number of the characters copied so far plus the
1665      * character that are to be copied is less than or equal to the desired length.
1666      * </p>
1667      *
1668      * @param runAheadTarget the target index (where the characters were copied to) pointing after the last character copied
1669      *        when the current part was copied.
1670      * @param source the source index (where the characters were copied from) pointing after the last character copied when
1671      *        the current part was copied.
1672      * @param originalLength the original length of the class full name, which is abbreviated.
1673      * @param desiredLength the desired length of the abbreviated class name.
1674      * @return {@code true} if it can be kept in its original length; {@code false} if the current part has to be abbreviated.
1675      */
1676     private static boolean useFull(final int runAheadTarget, final int source, final int originalLength, final int desiredLength) {
1677         return source >= originalLength || runAheadTarget + originalLength - source <= desiredLength;
1678     }
1679 
1680     /**
1681      * Converts the specified array of wrapper Class objects to an array of its corresponding primitive Class objects.
1682      *
1683      * <p>
1684      * This method invokes {@code wrapperToPrimitive()} for each element of the passed in array.
1685      * </p>
1686      *
1687      * @param classes the class array to convert, may be null or empty.
1688      * @return an array which contains for each given class, the primitive class or <strong>null</strong> if the original class is not a wrapper class.
1689      *         {@code null} if null input. Empty array if an empty array passed in.
1690      * @see #wrapperToPrimitive(Class)
1691      * @since 2.4
1692      */
1693     public static Class<?>[] wrappersToPrimitives(final Class<?>... classes) {
1694         if (classes == null) {
1695             return null;
1696         }
1697         if (classes.length == 0) {
1698             return classes;
1699         }
1700         return ArrayUtils.setAll(new Class[classes.length], i -> wrapperToPrimitive(classes[i]));
1701     }
1702 
1703     /**
1704      * Converts the specified wrapper class to its corresponding primitive class.
1705      *
1706      * <p>
1707      * This method is the counter part of {@code primitiveToWrapper()}. If the passed in class is a wrapper class for a
1708      * primitive type, this primitive type will be returned (e.g. {@code Integer.TYPE} for {@code Integer.class}). For other
1709      * classes, or if the parameter is <strong>null</strong>, the return value is <strong>null</strong>.
1710      * </p>
1711      *
1712      * @param cls the class to convert, may be <strong>null</strong>.
1713      * @return the corresponding primitive type if {@code cls} is a wrapper class, <strong>null</strong> otherwise.
1714      * @see #primitiveToWrapper(Class)
1715      * @since 2.4
1716      */
1717     public static Class<?> wrapperToPrimitive(final Class<?> cls) {
1718         return WRAPPER_PRIMITIVE_MAP.get(cls);
1719     }
1720 
1721     /**
1722      * ClassUtils instances should NOT be constructed in standard programming. Instead, the class should be used as
1723      * {@code ClassUtils.getShortClassName(cls)}.
1724      *
1725      * <p>
1726      * This constructor is public to permit tools that require a JavaBean instance to operate.
1727      * </p>
1728      *
1729      * @deprecated TODO Make private in 4.0.
1730      */
1731     @Deprecated
1732     public ClassUtils() {
1733         // empty
1734     }
1735 
1736 }