Module org.junit.platform.commons

Package org.junit.platform.commons.util

Class ReflectionUtils

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 enum	ReflectionUtils.HierarchyTraversalMode	Modes in which a hierarchy can be traversed — for example, when searching for methods or fields within a class hierarchy.

Method Summary

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)
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, non-synthetic Constructor for the supplied class.
static String	getFullyQualifiedMethodName(Class<?> clazz, Method method)	Build the fully qualified method name for the method described by the supplied class and method.
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)	Deprecated. Please discontinue use of this method since it relies on internal implementation details of the JDK that may not work in the future.
static Method	getRequiredMethod(Class<?> clazz, String methodName, Class<?>... parameterTypes)	Find the first Method of the supplied class or interface that meets the specified criteria, 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 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(Class<?> sourceType, Class<?> targetType)	Determine if an object of the supplied source type can be assigned to the supplied target type for the purpose of reflective method invocations.
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	isFinal(Class<?> clazz)
static boolean	isFinal(Member member)
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	isMultidimensionalArray(Object obj)	Determine if the supplied object is a multidimensional array.
static boolean	isNotFinal(Class<?> clazz)
static boolean	isNotFinal(Member member)
static boolean	isNotPrivate(Class<?> clazz)
static boolean	isNotPrivate(Member member)
static boolean	isNotStatic(Class<?> clazz)
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)	Deprecated. Please use tryToLoadClass(String) instead.
static Optional<Class<?>>	loadClass(String name, ClassLoader classLoader)	Deprecated. Please use tryToLoadClass(String, ClassLoader) instead.
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)	Deprecated. Please use tryToReadFieldValue(Class, String, Object) instead.
static Optional<Object>	readFieldValue(Field field)	Deprecated. Please use tryToReadFieldValue(Field) instead.
static Optional<Object>	readFieldValue(Field field, Object instance)	Deprecated. Please use tryToReadFieldValue(Field, Object) instead.
static List<Object>	readFieldValues(List<Field> fields, Object instance)	Read the values of the supplied fields, making each field accessible if necessary and masking any checked exception as an unchecked exception.
static List<Object>	readFieldValues(List<Field> fields, Object instance, Predicate<Field> predicate)	Read the values of the supplied fields, making each field accessible if necessary, masking any checked exception as an unchecked exception, and filtering out fields that do not pass the supplied predicate.
static Class<?>[]	resolveParameterTypes(Class<?> clazz, String methodName, String parameterTypeNames)
static boolean	returnsVoid(Method method)
static Stream<Class<?>>	streamAllClassesInClasspathRoot(URI root, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)
static Stream<Class<?>>	streamAllClassesInClasspathRoot(URI root, ClassFilter classFilter)
static Stream<Class<?>>	streamAllClassesInModule(String moduleName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)
static Stream<Class<?>>	streamAllClassesInModule(String moduleName, ClassFilter classFilter)
static Stream<Class<?>>	streamAllClassesInPackage(String basePackageName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)	since 1.10
static Stream<Class<?>>	streamAllClassesInPackage(String basePackageName, ClassFilter classFilter)
static Stream<Field>	streamFields(Class<?> clazz, Predicate<Field> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)
static Stream<Method>	streamMethods(Class<?> clazz, Predicate<Method> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)
static Stream<Class<?>>	streamNestedClasses(Class<?> clazz, Predicate<Class<?>> predicate)	since 1.10
static Try<Method>	tryToGetMethod(Class<?> clazz, String methodName, Class<?>... parameterTypes)	Try to get the Method in the specified class with the specified name and parameter types.
static Try<Class<?>>	tryToLoadClass(String name)
static Try<Class<?>>	tryToLoadClass(String name, ClassLoader classLoader)	Try to load a class by its primitive name or fully qualified name, using the supplied ClassLoader.
static <T> Try<Object>	tryToReadFieldValue(Class<T> clazz, String fieldName, T instance)	Try to read the value of a potentially inaccessible or nonexistent field.
static Try<Object>	tryToReadFieldValue(Field field)	Try to read the value of a potentially inaccessible static field.
static Try<Object>	tryToReadFieldValue(Field field, Object instance)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

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

@API(status=INTERNAL,
     since="1.4")
public static boolean isNotPrivate(Class<?> clazz)

isNotPrivate

@API(status=INTERNAL,
     since="1.1")
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)

isNotStatic

@API(status=INTERNAL,
     since="1.4")
public static boolean isNotStatic(Class<?> clazz)

isStatic

public static boolean isStatic(Member member)

isNotStatic

@API(status=INTERNAL,
     since="1.1")
public static boolean isNotStatic(Member member)

isFinal

@API(status=INTERNAL,
     since="1.5")
public static boolean isFinal(Class<?> clazz)

Since:

1.5

isNotFinal

@API(status=INTERNAL,
     since="1.5")
public static boolean isNotFinal(Class<?> clazz)

Since:

1.5

isFinal

@API(status=INTERNAL,
     since="1.5")
public static boolean isFinal(Member member)

Since:

1.5

isNotFinal

@API(status=INTERNAL,
     since="1.5")
public static boolean isNotFinal(Member member)

Since:

1.5

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

isMultidimensionalArray

@API(status=INTERNAL,
     since="1.3.2")
public static boolean isMultidimensionalArray(Object obj)

Determine if the supplied object is a multidimensional array.

Parameters:

obj - the object to test; potentially null

Returns:

true if the object is a multidimensional array

Since:

1.3.2

isAssignableTo

public static boolean isAssignableTo(Class<?> sourceType,
 Class<?> targetType)

Determine if an object of the supplied source type can be assigned to the supplied target type for the purpose of reflective method invocations.

In contrast to Class.isAssignableFrom(Class), this method returns true if the target type represents a primitive type whose wrapper matches the supplied source type. In addition, this method also supports widening conversions for primitive target types.

Parameters:

sourceType - the non-primitive target type; never null

targetType - the target type; never null

Returns:

true if an object of the source type is assignment compatible with the target type

Since:

1.8

See Also:

• Class.isInstance(Object)
• Class.isAssignableFrom(Class)
• isAssignableTo(Object, Class)

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)
• isAssignableTo(Class, 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

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static <T> Optional<Object> readFieldValue(Class<T> clazz,
 String fieldName,
 T instance)

Deprecated.

Please use tryToReadFieldValue(Class, String, Object) instead.

Read the value of a potentially inaccessible or nonexistent field.

If the field does not exist or the value of the field is null, an empty Optional will be 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)

tryToReadFieldValue

@API(status=INTERNAL,
     since="1.4")
public static <T> Try<Object> tryToReadFieldValue(Class<T> clazz,
 String fieldName,
 T instance)

Try to read the value of a potentially inaccessible or nonexistent field.

If the field does not exist or an exception occurs while reading it, a failed Try is returned that contains the corresponding exception.

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

Since:

1.4

See Also:

• tryToReadFieldValue(Field)
• tryToReadFieldValue(Field, Object)

readFieldValue

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static Optional<Object> readFieldValue(Field field)

Deprecated.

Please use tryToReadFieldValue(Field) instead.

Read the value of the supplied static field, making it accessible if necessary and masking any checked exception as an unchecked exception.

If the value of the field is null, an empty Optional will be returned.

Parameters:

field - the field to read; never null

See Also:

• readFieldValue(Field, Object)
• readFieldValue(Class, String, Object)

tryToReadFieldValue

@API(status=INTERNAL,
     since="1.4")
public static Try<Object> tryToReadFieldValue(Field field)

Try to read the value of a potentially inaccessible static field.

If an exception occurs while reading the field, a failed Try is returned that contains the corresponding exception.

Parameters:

field - the field to read; never null

Since:

1.4

See Also:

• tryToReadFieldValue(Field, Object)
• tryToReadFieldValue(Class, String, Object)

readFieldValue

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static Optional<Object> readFieldValue(Field field,
 Object instance)

Deprecated.

Please use tryToReadFieldValue(Field, Object) instead.

Read the value of the supplied field, making it accessible if necessary and masking any checked exception as an unchecked exception.

If the value of the field is null, an empty Optional will be 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)

tryToReadFieldValue

@API(status=INTERNAL,
     since="1.4")
public static Try<Object> tryToReadFieldValue(Field field,
 Object instance)

Since:

1.4

See Also:

• ReflectionSupport.tryToReadFieldValue(Field, Object)
• tryToReadFieldValue(Class, String, Object)

readFieldValues

public static List<Object> readFieldValues(List<Field> fields,
 Object instance)

Read the values of the supplied fields, making each field accessible if necessary and masking any checked exception as an unchecked exception.

Parameters:

fields - the list of fields to read; never null

instance - the instance from which the values are to be read; may be null for static fields

Returns:

an immutable list of the values of the specified fields; never null but may be empty or contain null entries

readFieldValues

public static List<Object> readFieldValues(List<Field> fields,
 Object instance,
 Predicate<Field> predicate)

Read the values of the supplied fields, making each field accessible if necessary, masking any checked exception as an unchecked exception, and filtering out fields that do not pass the supplied predicate.

Parameters:

fields - the list of fields to read; never null

instance - the instance from which the values are to be read; may be null for static fields

predicate - the field filter; never null

Returns:

an immutable list of the values of the specified fields; never null but may be empty or contain null entries

invokeMethod

public static Object invokeMethod(Method method,
 Object target,
 Object... args)

See Also:

• ReflectionSupport.invokeMethod(Method, Object, Object...)

loadClass

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static Optional<Class<?>> loadClass(String name)

Deprecated.

Please use tryToLoadClass(String) instead.

See Also:

• ReflectionSupport.loadClass(String)

tryToLoadClass

@API(status=INTERNAL,
     since="1.4")
public static Try<Class<?>> tryToLoadClass(String name)

Since:

1.4

See Also:

• ReflectionSupport.tryToLoadClass(String)

loadClass

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static Optional<Class<?>> loadClass(String name,
 ClassLoader classLoader)

Deprecated.

Please use tryToLoadClass(String, ClassLoader) instead.

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)

tryToLoadClass

@API(status=INTERNAL,
     since="1.4")
public static Try<Class<?>> tryToLoadClass(String name,
 ClassLoader classLoader)

Try to load a class by its primitive name or fully qualified name, using the supplied ClassLoader.

See ReflectionSupport.tryToLoadClass(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

Since:

1.4

See Also:

• tryToLoadClass(String)

getFullyQualifiedMethodName

public static String getFullyQualifiedMethodName(Class<?> clazz,
 Method method)

Build the fully qualified method name for the method described by the supplied class and method.

Note that the class is not necessarily the class in which the method is declared.

Parameters:

clazz - the class from which the method should be referenced; never null

method - the method; never null

Returns:

fully qualified method name; never null

Since:

1.4

See Also:

• getFullyQualifiedMethodName(Class, String, Class...)

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.

Note that the class is not necessarily the class in which the method is declared.

Parameters:

clazz - the class from which the method should be referenced; 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

See Also:

• getFullyQualifiedMethodName(Class, Method)

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

@API(status=DEPRECATED,
     since="1.4")
@Deprecated
public static Optional<Object> getOutermostInstance(Object inner,
 Class<?> requiredType)

Deprecated.

Please discontinue use of this method since it relies on internal implementation details of the JDK that may not work in the future.

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 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)

streamAllClassesInClasspathRoot

public static Stream<Class<?>> streamAllClassesInClasspathRoot(URI root,
 Predicate<Class<?>> classFilter,
 Predicate<String> classNameFilter)

Since:

1.10

See Also:

• ReflectionSupport.streamAllClassesInClasspathRoot(URI, Predicate, Predicate)

findAllClassesInClasspathRoot

public static List<Class<?>> findAllClassesInClasspathRoot(URI root,
 ClassFilter classFilter)

Since:

1.1

streamAllClassesInClasspathRoot

public static Stream<Class<?>> streamAllClassesInClasspathRoot(URI root,
 ClassFilter classFilter)

Since:

1.10

findAllClassesInPackage

public static List<Class<?>> findAllClassesInPackage(String basePackageName,
 Predicate<Class<?>> classFilter,
 Predicate<String> classNameFilter)

See Also:

• ReflectionSupport.findAllClassesInPackage(String, Predicate, Predicate)

streamAllClassesInPackage

public static Stream<Class<?>> streamAllClassesInPackage(String basePackageName,
 Predicate<Class<?>> classFilter,
 Predicate<String> classNameFilter)

since 1.10

See Also:

• ReflectionSupport.streamAllClassesInPackage(String, Predicate, Predicate)

findAllClassesInPackage

public static List<Class<?>> findAllClassesInPackage(String basePackageName,
 ClassFilter classFilter)

Since:

1.1

streamAllClassesInPackage

public static Stream<Class<?>> streamAllClassesInPackage(String basePackageName,
 ClassFilter classFilter)

Since:

1.10

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)

streamAllClassesInModule

public static Stream<Class<?>> streamAllClassesInModule(String moduleName,
 Predicate<Class<?>> classFilter,
 Predicate<String> classNameFilter)

Since:

1.10

See Also:

• ReflectionSupport.streamAllClassesInModule(String, Predicate, Predicate)

findAllClassesInModule

public static List<Class<?>> findAllClassesInModule(String moduleName,
 ClassFilter classFilter)

Since:

1.1.1

streamAllClassesInModule

public static Stream<Class<?>> streamAllClassesInModule(String moduleName,
 ClassFilter classFilter)

Since:

1.10

findNestedClasses

public static List<Class<?>> findNestedClasses(Class<?> clazz,
 Predicate<Class<?>> predicate)

See Also:

• ReflectionSupport.findNestedClasses(Class, Predicate)

streamNestedClasses

public static Stream<Class<?>> streamNestedClasses(Class<?> clazz,
 Predicate<Class<?>> predicate)

since 1.10

See Also:

• ReflectionSupport.streamNestedClasses(Class, Predicate)

getDeclaredConstructor

public static <T> Constructor<T> getDeclaredConstructor(Class<T> clazz)

Get the sole declared, non-synthetic Constructor for the supplied class.

Throws a PreconditionViolationException if the supplied class declares more than one non-synthetic constructor.

Parameters:

clazz - the class to get the constructor for

Returns:

the sole declared constructor; never null

See Also:

• Class.getDeclaredConstructors()
• Class.isSynthetic()

findConstructors

public static List<Constructor<?>> findConstructors(Class<?> clazz,
 Predicate<Constructor<?>> predicate)

Find all constructors in the supplied class that match the supplied predicate.

Note that this method may return synthetic constructors. If you wish to ignore synthetic constructors, you may filter them out with the supplied predicate or filter them out of the list returned by this method.

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

See Also:

• Class.getDeclaredConstructors()
• Class.isSynthetic()

findFields

public static List<Field> findFields(Class<?> clazz,
 Predicate<Field> predicate,
 ReflectionUtils.HierarchyTraversalMode traversalMode)

See Also:

• ReflectionSupport.findFields(Class, Predicate, org.junit.platform.commons.support.HierarchyTraversalMode)

streamFields

public static Stream<Field> streamFields(Class<?> clazz,
 Predicate<Field> predicate,
 ReflectionUtils.HierarchyTraversalMode traversalMode)

Since:

1.10

See Also:

• ReflectionSupport.streamFields(Class, Predicate, org.junit.platform.commons.support.HierarchyTraversalMode)

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...)

tryToGetMethod

@API(status=INTERNAL,
     since="1.4")
public static Try<Method> tryToGetMethod(Class<?> clazz,
 String methodName,
 Class<?>... parameterTypes)

Try to get the Method in the specified class with the specified name and parameter types.

This method delegates to Class.getMethod(String, Class...) but catches any exception thrown.

Parameters:

clazz - the class in which to search for the method; never null

methodName - the name of the method to get; never null or blank

parameterTypes - the parameter types of the method; may be null or empty

Returns:

a successful Try containing the method or a failed Try containing the NoSuchMethodException thrown by Class#getMethod(); never null

Since:

1.4

findMethod

public static Optional<Method> findMethod(Class<?> clazz,
 String methodName,
 String parameterTypeNames)

See Also:

• ReflectionSupport.findMethod(Class, String, String)

resolveParameterTypes

@API(status=INTERNAL,
     since="1.10")
public static Class<?>[] resolveParameterTypes(Class<?> clazz,
 String methodName,
 String parameterTypeNames)

findMethod

public static Optional<Method> findMethod(Class<?> clazz,
 String methodName,
 Class<?>... parameterTypes)

See Also:

• ReflectionSupport.findMethod(Class, String, Class...)

getRequiredMethod

@API(status=STABLE,
     since="1.7")
public static Method getRequiredMethod(Class<?> clazz,
 String methodName,
 Class<?>... parameterTypes)

Find the first Method of the supplied class or interface that meets the specified criteria, 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.

Use this method as an alternative to findMethod(Class, String, Class...) for use cases in which the method is required to be present.

Parameters:

clazz - the class or interface in which to find the method; never null

methodName - the name of the method to find; never null or empty

parameterTypes - the types of parameters accepted by the method, if any; never null

Returns:

the Method found; never null

Throws:

JUnitException - if no method is found

Since:

1.7

See Also:

• 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)

streamMethods

public static Stream<Method> streamMethods(Class<?> clazz,
 Predicate<Method> predicate,
 ReflectionUtils.HierarchyTraversalMode traversalMode)

Since:

1.10

See Also:

• ReflectionSupport.streamMethods(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<?>)