Module java.base
Package java.lang.reflect

Class Executable

java.lang.Object
java.lang.reflect.AccessibleObject
java.lang.reflect.Executable
All Implemented Interfaces:
AnnotatedElement, GenericDeclaration, Member
Direct Known Subclasses:
Constructor, Method
public abstract class Executable extends AccessibleObject implements Member, GenericDeclaration
A shared superclass for the common functionality of Method and Constructor.
Since:
1.8

  • Method Details

    • getDeclaringClass

      public abstract Class<?> getDeclaringClass()
      Returns the Class object representing the class or interface that declares the executable represented by this object.
      Specified by:
      getDeclaringClass in interface Member
      Returns:
      an object representing the declaring class of the underlying member

    • getName

      public abstract String getName()
      Returns the name of the executable represented by this object.
      Specified by:
      getName in interface Member
      Returns:
      the simple name of the underlying member

    • getModifiers

      public abstract int getModifiers()
      Returns the Java language modifiers for the executable represented by this object.
      Specified by:
      getModifiers in interface Member
      Returns:
      the Java language modifiers for the underlying member
      See Also:
      Modifier

    • getTypeParameters

      public abstract TypeVariable<?>[] getTypeParameters()
      Returns an array of TypeVariable objects that represent the type variables declared by the generic declaration represented by this GenericDeclaration object, in declaration order. Returns an array of length 0 if the underlying generic declaration declares no type variables.
      Specified by:
      getTypeParameters in interface GenericDeclaration
      Returns:
      an array of TypeVariable objects that represent the type variables declared by this generic declaration
      Throws:
      GenericSignatureFormatError - if the generic signature of this generic declaration does not conform to the format specified in The Java Virtual Machine Specification

    • getParameterTypes

      public abstract Class<?>[] getParameterTypes()
      Returns an array of Class objects that represent the formal parameter types, in declaration order, of the executable represented by this object. Returns an array of length 0 if the underlying executable takes no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.
      Returns:
      the parameter types for the executable this object represents

    • getParameterCount

      public int getParameterCount()
      Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object.
      Returns:
      The number of formal parameters for the executable this object represents

    • getGenericParameterTypes

      public Type[] getGenericParameterTypes()
      Returns an array of Type objects that represent the formal parameter types, in declaration order, of the executable represented by this object. Returns an array of length 0 if the underlying executable takes no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.

      If a formal parameter type is a parameterized type, the Type object returned for it must accurately reflect the actual type arguments used in the source code.

      If a formal parameter type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

      Returns:
      an array of Types that represent the formal parameter types of the underlying executable, in declaration order
      Throws:
      GenericSignatureFormatError - if the generic method signature does not conform to the format specified in The Java Virtual Machine Specification
      TypeNotPresentException - if any of the parameter types of the underlying executable refers to a non-existent type declaration
      MalformedParameterizedTypeException - if any of the underlying executable's parameter types refer to a parameterized type that cannot be instantiated for any reason

    • getParameters

      public Parameter[] getParameters()
      Returns an array of Parameter objects that represent all the parameters to the underlying executable represented by this object. Returns an array of length 0 if the executable has no parameters.

      The parameters of the underlying executable do not necessarily have unique names, or names that are legal identifiers in the Java programming language (JLS 3.8).

      Returns:
      an array of Parameter objects representing all the parameters to the executable this object represents.
      Throws:
      MalformedParametersException - if the class file contains a MethodParameters attribute that is improperly formatted.

    • getExceptionTypes

      public abstract Class<?>[] getExceptionTypes()
      Returns an array of Class objects that represent the types of exceptions declared to be thrown by the underlying executable represented by this object. Returns an array of length 0 if the executable declares no exceptions in its throws clause.
      Returns:
      the exception types declared as being thrown by the executable this object represents

    • getGenericExceptionTypes

      public Type[] getGenericExceptionTypes()
      Returns an array of Type objects that represent the exceptions declared to be thrown by this executable object. Returns an array of length 0 if the underlying executable declares no exceptions in its throws clause.

      If an exception type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

      Returns:
      an array of Types that represent the exception types thrown by the underlying executable
      Throws:
      GenericSignatureFormatError - if the generic method signature does not conform to the format specified in The Java Virtual Machine Specification
      TypeNotPresentException - if the underlying executable's throws clause refers to a non-existent type declaration
      MalformedParameterizedTypeException - if the underlying executable's throws clause refers to a parameterized type that cannot be instantiated for any reason

    • toGenericString

      public abstract String toGenericString()
      Returns a string describing this Executable, including any type parameters.
      Returns:
      a string describing this Executable, including any type parameters

    • isVarArgs

      public boolean isVarArgs()
      Returns true if this executable was declared to take a variable number of arguments; returns false otherwise.
      Returns:
      true if an only if this executable was declared to take a variable number of arguments.

    • isSynthetic

      public boolean isSynthetic()
      Returns true if this executable is a synthetic construct; returns false otherwise.
      Specified by:
      isSynthetic in interface Member
      Returns:
      true if and only if this executable is a synthetic construct as defined by The Java Language Specification.
      See Java Language Specification:
      13.1 The Form of a Binary

    • getParameterAnnotations

      public abstract Annotation[][] getParameterAnnotations()
      Returns an array of arrays of Annotations that represent the annotations on the formal parameters, in declaration order, of the Executable represented by this object. Synthetic and mandated parameters (see explanation below), such as the outer "this" parameter to an inner class constructor will be represented in the returned array. If the executable has no parameters (meaning no formal, no synthetic, and no mandated parameters), a zero-length array will be returned. If the Executable has one or more parameters, a nested array of length zero is returned for each parameter with no annotations. The annotation objects contained in the returned arrays are serializable. The caller of this method is free to modify the returned arrays; it will have no effect on the arrays returned to other callers. A compiler may add extra parameters that are implicitly declared in source ("mandated"), as well as parameters that are neither implicitly nor explicitly declared in source ("synthetic") to the parameter list for a method. See Parameter for more information.

      Note that any annotations returned by this method are declaration annotations.

      Returns:
      an array of arrays that represent the annotations on the formal and implicit parameters, in declaration order, of the executable represented by this object
      See Also:
      Parameter, Parameter.getAnnotations()

    • getAnnotation

      public <T extends Annotation> T getAnnotation​(Class<T> annotationClass)
      Returns this element's annotation for the specified type if such an annotation is present, else null.

      Note that any annotation returned by this method is a declaration annotation.

      Specified by:
      getAnnotation in interface AnnotatedElement
      Overrides:
      getAnnotation in class AccessibleObject
      Type Parameters:
      T - the type of the annotation to query for and return if present
      Parameters:
      annotationClass - the Class object corresponding to the annotation type
      Returns:
      this element's annotation for the specified annotation type if present on this element, else null
      Throws:
      NullPointerException - if the given annotation class is null

    • getAnnotationsByType

      public <T extends Annotation> T[] getAnnotationsByType​(Class<T> annotationClass)
      Returns annotations that are associated with this element. If there are no annotations associated with this element, the return value is an array of length 0. The difference between this method and AnnotatedElement.getAnnotation(Class) is that this method detects if its argument is a repeatable annotation type (JLS 9.6), and if so, attempts to find one or more annotations of that type by "looking through" a container annotation. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.

      Note that any annotations returned by this method are declaration annotations.

      Specified by:
      getAnnotationsByType in interface AnnotatedElement
      Overrides:
      getAnnotationsByType in class AccessibleObject
      Type Parameters:
      T - the type of the annotation to query for and return if present
      Parameters:
      annotationClass - the Class object corresponding to the annotation type
      Returns:
      all this element's annotations for the specified annotation type if associated with this element, else an array of length zero
      Throws:
      NullPointerException - if the given annotation class is null

    • getDeclaredAnnotations

      public Annotation[] getDeclaredAnnotations()
      Returns annotations that are directly present on this element. This method ignores inherited annotations. If there are no annotations directly present on this element, the return value is an array of length 0. The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.

      Note that any annotations returned by this method are declaration annotations.

      Specified by:
      getDeclaredAnnotations in interface AnnotatedElement
      Overrides:
      getDeclaredAnnotations in class AccessibleObject
      Returns:
      annotations directly present on this element

    • getAnnotatedReturnType

      public abstract AnnotatedType getAnnotatedReturnType()
      Returns an AnnotatedType object that represents the use of a type to specify the return type of the method/constructor represented by this Executable. If this Executable object represents a constructor, the AnnotatedType object represents the type of the constructed object. If this Executable object represents a method, the AnnotatedType object represents the use of a type to specify the return type of the method.
      Returns:
      an object representing the return type of the method or constructor represented by this Executable

    • getAnnotatedReceiverType

      public AnnotatedType getAnnotatedReceiverType()
      Returns an AnnotatedType object that represents the use of a type to specify the receiver type of the method/constructor represented by this Executable object. The receiver type of a method/constructor is available only if the method/constructor has a receiver parameter (JLS 8.4.1). If this Executable object represents an instance method or represents a constructor of an inner member class, and the method/constructor either has no receiver parameter or has a receiver parameter with no annotations on its type, then the return value is an AnnotatedType object representing an element with no annotations. If this Executable object represents a static method or represents a constructor of a top level, static member, local, or anonymous class, then the return value is null.
      Returns:
      an object representing the receiver type of the method or constructor represented by this Executable or null if this Executable can not have a receiver parameter
      See Java Language Specification:
      8.4 Method Declarations
      8.4.1 Formal Parameters
      8.8 Constructor Declarations

    • getAnnotatedParameterTypes

      public AnnotatedType[] getAnnotatedParameterTypes()
      Returns an array of AnnotatedType objects that represent the use of types to specify formal parameter types of the method/constructor represented by this Executable. The order of the objects in the array corresponds to the order of the formal parameter types in the declaration of the method/constructor. Returns an array of length 0 if the method/constructor declares no parameters. Note that the constructors of some inner classes may have an implicitly declared parameter in addition to explicitly declared ones.
      Returns:
      an array of objects representing the types of the formal parameters of the method or constructor represented by this Executable

    • getAnnotatedExceptionTypes

      public AnnotatedType[] getAnnotatedExceptionTypes()
      Returns an array of AnnotatedType objects that represent the use of types to specify the declared exceptions of the method/constructor represented by this Executable. The order of the objects in the array corresponds to the order of the exception types in the declaration of the method/constructor. Returns an array of length 0 if the method/constructor declares no exceptions.
      Returns:
      an array of objects representing the declared exceptions of the method or constructor represented by this Executable