java.lang.Object
- org.junit.platform.commons.util.ReflectionUtils

```
@API(status=INTERNAL,
     since="1.0")
public final class ReflectionUtils
extends Object
```
Collection of utilities for working with the Java reflection APIs.
DISCLAIMER

These utilities are intended solely for usage within the JUnit framework itself. Any usage by external parties is not supported. Use at your own risk!
Some utilities are published via the maintained ReflectionSupport class.

Since:

1.0

See Also:

ReflectionSupport

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ReflectionUtils.HierarchyTraversalMode`	Modes in which a hierarchy can be traversed — for example, when searching for methods or fields within a class hierarchy.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static List<Class<?>>`	`findAllClassesInClasspathRoot(URI root, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)`
`static List<Class<?>>`	`findAllClassesInClasspathRoot(URI root, ClassFilter classFilter)`
`static List<Class<?>>`	`findAllClassesInModule(String moduleName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)`
`static List<Class<?>>`	`findAllClassesInModule(String moduleName, ClassFilter classFilter)`
`static List<Class<?>>`	`findAllClassesInPackage(String basePackageName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)`
`static List<Class<?>>`	`findAllClassesInPackage(String basePackageName, ClassFilter classFilter)`
`static List<Constructor<?>>`	`findConstructors(Class<?> clazz, Predicate<Constructor<?>> predicate)`	Find all constructors in the supplied class that match the supplied predicate.
`static List<Field>`	`findFields(Class<?> clazz, Predicate<Field> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)`	Find all fields of the supplied class or interface that match the specified `predicate`.
`static Optional<Method>`	`findMethod(Class<?> clazz, String methodName, Class<?>... parameterTypes)`
`static Optional<Method>`	`findMethod(Class<?> clazz, String methodName, String parameterTypeNames)`
`static List<Method>`	`findMethods(Class<?> clazz, Predicate<Method> predicate)`	Find all methods of the supplied class or interface that match the specified `predicate`, using top-down search semantics within the type hierarchy.
`static List<Method>`	`findMethods(Class<?> clazz, Predicate<Method> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)`
`static List<Class<?>>`	`findNestedClasses(Class<?> clazz, Predicate<Class<?>> predicate)`
`static Set<Class<?>>`	`getAllAssignmentCompatibleClasses(Class<?> clazz)`	Return all classes and interfaces that can be used as assignment types for instances of the specified `Class`, including itself.
`static Set<Path>`	`getAllClasspathRootDirectories()`
`static <T> Constructor<T>`	`getDeclaredConstructor(Class<T> clazz)`	Get the sole declared `Constructor` for the supplied class.
`static String`	`getFullyQualifiedMethodName(Class<?> clazz, String methodName, Class<?>... parameterTypes)`	Build the fully qualified method name for the method described by the supplied class, method name, and parameter types.
`static Optional<Object>`	`getOutermostInstance(Object inner, Class<?> requiredType)`	Get the outermost instance of the required type, searching recursively through enclosing instances.
`static Class<?>`	`getWrapperType(Class<?> type)`	Get the wrapper type for the supplied primitive type.
`static Object`	`invokeMethod(Method method, Object target, Object... args)`
`static boolean`	`isAbstract(Class<?> clazz)`
`static boolean`	`isAbstract(Member member)`
`static boolean`	`isArray(Object obj)`	Determine if the supplied object is an array.
`static boolean`	`isAssignableTo(Object obj, Class<?> targetType)`	Determine if the supplied object can be assigned to the supplied target type for the purpose of reflective method invocations.
`static boolean`	`isInnerClass(Class<?> clazz)`	Determine if the supplied class is an inner class (i.e., a non-static member class).
`static boolean`	`isMethodPresent(Class<?> clazz, Predicate<Method> predicate)`	Determine if a `Method` matching the supplied `Predicate` is present within the type hierarchy of the specified class, beginning with the specified class or interface and traversing up the type hierarchy until such a method is found or the type hierarchy is exhausted.
`static boolean`	`isNotPrivate(Member member)`
`static boolean`	`isNotStatic(Member member)`
`static boolean`	`isPrivate(Class<?> clazz)`
`static boolean`	`isPrivate(Member member)`
`static boolean`	`isPublic(Class<?> clazz)`
`static boolean`	`isPublic(Member member)`
`static boolean`	`isStatic(Class<?> clazz)`
`static boolean`	`isStatic(Member member)`
`static Optional<Class<?>>`	`loadClass(String name)`
`static Optional<Class<?>>`	`loadClass(String name, ClassLoader classLoader)`	Load a class by its primitive name or fully qualified name, using the supplied `ClassLoader`.
`static <T extends AccessibleObject> T`	`makeAccessible(T object)`
`static <T> T`	`newInstance(Class<T> clazz, Object... args)`
`static <T> T`	`newInstance(Constructor<T> constructor, Object... args)`	Create a new instance of type `T` by invoking the supplied constructor with the supplied arguments.
`static String[]`	`parseFullyQualifiedMethodName(String fullyQualifiedMethodName)`	Parse the supplied fully qualified method name into a 3-element `String[]` with the following content.
`static <T> Optional<Object>`	`readFieldValue(Class<T> clazz, String fieldName, T instance)`	Read the value of a potentially inaccessible or nonexistent field.
`static Optional<Object>`	`readFieldValue(Field field)`	Read the value of a potentially inaccessible static field.
`static <T> Optional<Object>`	`readFieldValue(Field field, T instance)`	Read the value of a potentially inaccessible field.
`static boolean`	`returnsVoid(Method method)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - isPublic
```
public static boolean isPublic(Class<?> clazz)
```
  - isPublic
```
public static boolean isPublic(Member member)
```
  - isPrivate
```
public static boolean isPrivate(Class<?> clazz)
```
  - isPrivate
```
public static boolean isPrivate(Member member)
```
  - isNotPrivate
```
public static boolean isNotPrivate(Member member)
```
  - isAbstract
```
public static boolean isAbstract(Class<?> clazz)
```
  - isAbstract
```
public static boolean isAbstract(Member member)
```
  - isStatic
```
public static boolean isStatic(Class<?> clazz)
```
  - isStatic
```
public static boolean isStatic(Member member)
```
  - isNotStatic
```
public static boolean isNotStatic(Member member)
```
  - isInnerClass
```
public static boolean isInnerClass(Class<?> clazz)
```
    Determine if the supplied class is an inner class (i.e., a non-static member class).
    Technically speaking (i.e., according to the Java Language Specification), "an inner class may be a non-static member class, a local class, or an anonymous class." However, this method does not return true for a local or anonymous class.
    
    Parameters:
    
    clazz - the class to check; never null
    
    Returns:
    
    true if the class is an inner class
  - returnsVoid
```
public static boolean returnsVoid(Method method)
```
  - isArray
```
public static boolean isArray(Object obj)
```
    Determine if the supplied object is an array.
    
    Parameters:
    
    obj - the object to test; potentially null
    
    Returns:
    
    true if the object is an array
  - isAssignableTo
```
public static boolean isAssignableTo(Object obj,
                                     Class<?> targetType)
```
    Determine if the supplied object can be assigned to the supplied target type for the purpose of reflective method invocations.
    In contrast to Class.isInstance(Object), this method returns true if the target type represents a primitive type whose wrapper matches the supplied object's type. In addition, this method also supports widening conversions for primitive types and their corresponding wrapper types.
    If the supplied object is null and the supplied type does not represent a primitive type, this method returns true.
    
    Parameters:
    
    obj - the object to test for assignment compatibility; potentially null
    
    targetType - the type to check against; never null
    
    Returns:
    
    true if the object is assignment compatible
    
    See Also:
    
    Class.isInstance(Object), Class.isAssignableFrom(Class)
  - getWrapperType
```
public static Class<?> getWrapperType(Class<?> type)
```
    Get the wrapper type for the supplied primitive type.
    
    Parameters:
    
    type - the primitive type for which to retrieve the wrapper type
    
    Returns:
    
    the corresponding wrapper type or null if the supplied type is null or not a primitive type
  - newInstance
```
public static <T> T newInstance(Class<T> clazz,
                                Object... args)
```
    See Also:
    
    ReflectionSupport.newInstance(Class, Object...), newInstance(Constructor, Object...)
  - newInstance
```
public static <T> T newInstance(Constructor<T> constructor,
                                Object... args)
```
    Create a new instance of type T by invoking the supplied constructor with the supplied arguments.
    The constructor will be made accessible if necessary, and any checked exception will be masked as an unchecked exception.
    
    Parameters:
    
    constructor - the constructor to invoke; never null
    
    args - the arguments to pass to the constructor
    
    Returns:
    
    the new instance; never null
    
    See Also:
    
    newInstance(Class, Object...), ExceptionUtils.throwAsUncheckedException(Throwable)
  - readFieldValue
```
public static <T> Optional<Object> readFieldValue(Class<T> clazz,
                                                  String fieldName,
                                                  T instance)
```
    Read the value of a potentially inaccessible or nonexistent field.
    If the field does not exist, an exception occurs while reading it, or the value of the field is null, an empty Optional is returned.
    
    Parameters:
    
    clazz - the class where the field is declared; never null
    
    fieldName - the name of the field; never null or empty
    
    instance - the instance from where the value is to be read; may be null for a static field
    
    See Also:
    
    readFieldValue(Field), readFieldValue(Field, Object)
  - readFieldValue
```
public static Optional<Object> readFieldValue(Field field)
```
    Read the value of a potentially inaccessible static field.
    If an exception occurs while reading the field or if the value of the field is null, an empty Optional is returned.
    
    Parameters:
    
    field - the field to read; never null
    
    See Also:
    
    readFieldValue(Field, Object), readFieldValue(Class, String, Object)
  - readFieldValue
```
public static <T> Optional<Object> readFieldValue(Field field,
                                                  T instance)
```
    Read the value of a potentially inaccessible field.
    If an exception occurs while reading the field or if the value of the field is null, an empty Optional is returned.
    
    Parameters:
    
    field - the field to read; never null
    
    instance - the instance from which the value is to be read; may be null for a static field
    
    See Also:
    
    readFieldValue(Field), readFieldValue(Class, String, Object)
  - invokeMethod
```
public static Object invokeMethod(Method method,
                                  Object target,
                                  Object... args)
```
    See Also:
    
    ReflectionSupport.invokeMethod(Method, Object, Object...)
  - loadClass
```
public static Optional<Class<?>> loadClass(String name)
```
    See Also:
    
    ReflectionSupport.loadClass(String)
  - loadClass
```
public static Optional<Class<?>> loadClass(String name,
                                           ClassLoader classLoader)
```
    Load a class by its primitive name or fully qualified name, using the supplied ClassLoader.
    See ReflectionSupport.loadClass(String) for details on support for class names for arrays.
    
    Parameters:
    
    name - the name of the class to load; never null or blank
    
    classLoader - the ClassLoader to use; never null
    
    See Also:
    
    loadClass(String)
  - getFullyQualifiedMethodName
```
public static String getFullyQualifiedMethodName(Class<?> clazz,
                                                 String methodName,
                                                 Class<?>... parameterTypes)
```
    Build the fully qualified method name for the method described by the supplied class, method name, and parameter types.
    
    Parameters:
    
    clazz - the class that declares the method; never null
    
    methodName - the name of the method; never null or blank
    
    parameterTypes - the parameter types of the method; may be null or empty
    
    Returns:
    
    fully qualified method name; never null
  - parseFullyQualifiedMethodName
```
public static String[] parseFullyQualifiedMethodName(String fullyQualifiedMethodName)
```
    Parse the supplied fully qualified method name into a 3-element String[] with the following content.
    
    index 0: the fully qualified class name
    
    index 1: the name of the method
    
    index 2: a comma-separated list of parameter types, or a blank string if the method does not declare any formal parameters
    Parameters:
    
    fullyQualifiedMethodName - a fully qualified method name, never null or blank
    
    Returns:
    
    a 3-element array of strings containing the parsed values
  - getOutermostInstance
```
public static Optional<Object> getOutermostInstance(Object inner,
                                                    Class<?> requiredType)
```
    Get the outermost instance of the required type, searching recursively through enclosing instances.
    If the supplied inner object is of the required type, it will simply be returned.
    
    Parameters:
    
    inner - the inner object from which to begin the search; never null
    
    requiredType - the required type of the outermost instance; never null
    
    Returns:
    
    an Optional containing the outermost instance; never null but potentially empty
  - getAllClasspathRootDirectories
```
public static Set<Path> getAllClasspathRootDirectories()
```
  - findAllClassesInClasspathRoot
```
public static List<Class<?>> findAllClassesInClasspathRoot(URI root,
                                                           Predicate<Class<?>> classFilter,
                                                           Predicate<String> classNameFilter)
```
    See Also:
    
    ReflectionSupport.findAllClassesInClasspathRoot(URI, Predicate, Predicate)
  - findAllClassesInClasspathRoot
```
public static List<Class<?>> findAllClassesInClasspathRoot(URI root,
                                                           ClassFilter classFilter)
```
    Since:
    
    1.1
  - findAllClassesInPackage
```
public static List<Class<?>> findAllClassesInPackage(String basePackageName,
                                                     Predicate<Class<?>> classFilter,
                                                     Predicate<String> classNameFilter)
```
    See Also:
    
    ReflectionSupport.findAllClassesInPackage(String, Predicate, Predicate)
  - findAllClassesInPackage
```
public static List<Class<?>> findAllClassesInPackage(String basePackageName,
                                                     ClassFilter classFilter)
```
    Since:
    
    1.1
  - findAllClassesInModule
```
public static List<Class<?>> findAllClassesInModule(String moduleName,
                                                    Predicate<Class<?>> classFilter,
                                                    Predicate<String> classNameFilter)
```
    Since:
    
    1.1.1
    
    See Also:
    
    ReflectionSupport.findAllClassesInModule(String, Predicate, Predicate)
  - findAllClassesInModule
```
public static List<Class<?>> findAllClassesInModule(String moduleName,
                                                    ClassFilter classFilter)
```
    Since:
    
    1.1.1
  - findNestedClasses
```
public static List<Class<?>> findNestedClasses(Class<?> clazz,
                                               Predicate<Class<?>> predicate)
```
    See Also:
    
    ReflectionSupport.findNestedClasses(Class, Predicate)
  - getDeclaredConstructor
```
public static <T> Constructor<T> getDeclaredConstructor(Class<T> clazz)
```
    Get the sole declared Constructor for the supplied class.
    Throws a PreconditionViolationException if the supplied class declares more than one constructor.
    
    Parameters:
    
    clazz - the class to get the constructor for
    
    Returns:
    
    the sole declared constructor; never null
    
    See Also:
    
    Class.getDeclaredConstructors()
  - findConstructors
```
public static List<Constructor<?>> findConstructors(Class<?> clazz,
                                                    Predicate<Constructor<?>> predicate)
```
    Find all constructors in the supplied class that match the supplied predicate.
    
    Parameters:
    
    clazz - the class in which to search for constructors; never null
    
    predicate - the predicate to use to test for a match; never null
    
    Returns:
    
    an immutable list of all such constructors found; never null but potentially empty
  - findFields
```
public static List<Field> findFields(Class<?> clazz,
                                     Predicate<Field> predicate,
                                     ReflectionUtils.HierarchyTraversalMode traversalMode)
```
    Find all fields of the supplied class or interface that match the specified predicate.
    The results will not contain fields that are hidden.
    
    Parameters:
    
    clazz - the class or interface in which to find the fields; never null
    
    predicate - the field filter; never null
    
    traversalMode - the hierarchy traversal mode; never null
    
    Returns:
    
    an immutable list of all such fields found; never null but potentially empty
  - isMethodPresent
```
public static boolean isMethodPresent(Class<?> clazz,
                                      Predicate<Method> predicate)
```
    Determine if a Method matching the supplied Predicate is present within the type hierarchy of the specified class, beginning with the specified class or interface and traversing up the type hierarchy until such a method is found or the type hierarchy is exhausted.
    
    Parameters:
    
    clazz - the class or interface in which to find the method; never null
    
    predicate - the predicate to use to test for a match; never null
    
    Returns:
    
    true if such a method is present
    
    See Also:
    
    findMethod(Class, String, String), findMethod(Class, String, Class...)
  - findMethod
```
public static Optional<Method> findMethod(Class<?> clazz,
                                          String methodName,
                                          String parameterTypeNames)
```
    See Also:
    
    ReflectionSupport.findMethod(Class, String, String)
  - findMethod
```
public static Optional<Method> findMethod(Class<?> clazz,
                                          String methodName,
                                          Class<?>... parameterTypes)
```
    See Also:
    
    ReflectionSupport.findMethod(Class, String, Class...)
  - findMethods
```
public static List<Method> findMethods(Class<?> clazz,
                                       Predicate<Method> predicate)
```
    Find all methods of the supplied class or interface that match the specified predicate, using top-down search semantics within the type hierarchy.
    The results will not contain instance methods that are overridden or static methods that are hidden.
    
    Parameters:
    
    clazz - the class or interface in which to find the methods; never null
    
    predicate - the method filter; never null
    
    Returns:
    
    an immutable list of all such methods found; never null
    
    See Also:
    
    ReflectionUtils.HierarchyTraversalMode.TOP_DOWN, findMethods(Class, Predicate, HierarchyTraversalMode)
  - findMethods
```
public static List<Method> findMethods(Class<?> clazz,
                                       Predicate<Method> predicate,
                                       ReflectionUtils.HierarchyTraversalMode traversalMode)
```
    See Also:
    
    ReflectionSupport.findMethods(Class, Predicate, org.junit.platform.commons.support.HierarchyTraversalMode)
  - makeAccessible
```
public static <T extends AccessibleObject> T makeAccessible(T object)
```
  - getAllAssignmentCompatibleClasses
```
public static Set<Class<?>> getAllAssignmentCompatibleClasses(Class<?> clazz)
```
    Return all classes and interfaces that can be used as assignment types for instances of the specified Class, including itself.
    
    Parameters:
    
    clazz - the Class to look up
    
    See Also:
    
    Class.isAssignableFrom(java.lang.Class<?>)

Class ReflectionUtils

DISCLAIMER

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

isPublic

isPublic

isPrivate

isPrivate

isNotPrivate

isAbstract

isAbstract

isStatic

isStatic

isNotStatic

isInnerClass

returnsVoid

isArray

isAssignableTo

getWrapperType

newInstance

newInstance

readFieldValue

readFieldValue

readFieldValue

invokeMethod

loadClass

loadClass

getFullyQualifiedMethodName

parseFullyQualifiedMethodName

getOutermostInstance

getAllClasspathRootDirectories

findAllClassesInClasspathRoot

findAllClassesInClasspathRoot

findAllClassesInPackage

findAllClassesInPackage

findAllClassesInModule

findAllClassesInModule

findNestedClasses

getDeclaredConstructor

findConstructors

findFields

isMethodPresent

findMethod

findMethod

findMethods

findMethods

makeAccessible

getAllAssignmentCompatibleClasses