https://openjdk.java.net/ 
/*
 * Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang.reflect;

import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.internal.misc.SharedSecrets;
import jdk.internal.reflect.CallerSensitive;
import jdk.internal.reflect.MethodAccessor;
import jdk.internal.reflect.Reflection;
import jdk.internal.vm.annotation.ForceInline;
import sun.reflect.annotation.ExceptionProxy;
import sun.reflect.annotation.TypeNotPresentExceptionProxy;
import sun.reflect.generics.repository.MethodRepository;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.scope.MethodScope;
import sun.reflect.annotation.AnnotationType;
import sun.reflect.annotation.AnnotationParser;
import java.lang.annotation.Annotation;
import java.lang.annotation.AnnotationFormatError;
import java.nio.ByteBuffer;
import java.util.StringJoiner;


A Method provides information about, and access to, a single method on a class or interface. The reflected method may be a class method or an instance method (including an abstract method). 
A Method permits widening conversions to occur when matching the actual parameters to invoke with the underlying method's formal parameters, but it throws an IllegalArgumentException if a narrowing conversion would occur. 
Author:Kenneth Russell, Nakul Saraiya
See Also:
Since:1.1
/**
 * A {@code Method} provides information about, and access to, a single method
 * on a class or interface.  The reflected method may be a class method
 * or an instance method (including an abstract method).
 *
 * <p>A {@code Method} permits widening conversions to occur when matching the
 * actual parameters to invoke with the underlying method's formal
 * parameters, but it throws an {@code IllegalArgumentException} if a
 * narrowing conversion would occur.
 *
 * @see Member
 * @see java.lang.Class
 * @see java.lang.Class#getMethods()
 * @see java.lang.Class#getMethod(String, Class[])
 * @see java.lang.Class#getDeclaredMethods()
 * @see java.lang.Class#getDeclaredMethod(String, Class[])
 *
 * @author Kenneth Russell
 * @author Nakul Saraiya
 * @since 1.1
 */
public final class Method extends Executable {
    private Class<?>            clazz;
    private int                 slot;
    // This is guaranteed to be interned by the VM in the 1.4
    // reflection implementation
    private String              name;
    private Class<?>            returnType;
    private Class<?>[]          parameterTypes;
    private Class<?>[]          exceptionTypes;
    private int                 modifiers;
    // Generics and annotations support
    private transient String              signature;
    // generic info repository; lazily initialized
    private transient MethodRepository genericInfo;
    private byte[]              annotations;
    private byte[]              parameterAnnotations;
    private byte[]              annotationDefault;
    private volatile MethodAccessor methodAccessor;
    // For sharing of MethodAccessors. This branching structure is
    // currently only two levels deep (i.e., one root Method and
    // potentially many Method objects pointing to it.)
    //
    // If this branching structure would ever contain cycles, deadlocks can
    // occur in annotation code.
    private Method              root;

    // Generics infrastructure
    private String getGenericSignature() {return signature;}

    // Accessor for factory
    private GenericsFactory getFactory() {
        // create scope and factory
        return CoreReflectionFactory.make(this, MethodScope.make(this));
    }

    // Accessor for generic info repository
    @Override
    MethodRepository getGenericInfo() {
        // lazily initialize repository if necessary
        if (genericInfo == null) {
            // create and cache generic info repository
            genericInfo = MethodRepository.make(getGenericSignature(),
                                                getFactory());
        }
        return genericInfo; //return cached repository
    }

    
Package-private constructor used by ReflectAccess to enable
instantiation of these objects in Java code from the java.lang
package via sun.reflect.LangReflectAccess.

/**
     * Package-private constructor used by ReflectAccess to enable
     * instantiation of these objects in Java code from the java.lang
     * package via sun.reflect.LangReflectAccess.
     */
    Method(Class<?> declaringClass,
           String name,
           Class<?>[] parameterTypes,
           Class<?> returnType,
           Class<?>[] checkedExceptions,
           int modifiers,
           int slot,
           String signature,
           byte[] annotations,
           byte[] parameterAnnotations,
           byte[] annotationDefault) {
        this.clazz = declaringClass;
        this.name = name;
        this.parameterTypes = parameterTypes;
        this.returnType = returnType;
        this.exceptionTypes = checkedExceptions;
        this.modifiers = modifiers;
        this.slot = slot;
        this.signature = signature;
        this.annotations = annotations;
        this.parameterAnnotations = parameterAnnotations;
        this.annotationDefault = annotationDefault;
    }

    
Package-private routine (exposed to java.lang.Class via
ReflectAccess) which returns a copy of this Method. The copy's
"root" field points to this Method.

/**
     * Package-private routine (exposed to java.lang.Class via
     * ReflectAccess) which returns a copy of this Method. The copy's
     * "root" field points to this Method.
     */
    Method copy() {
        // This routine enables sharing of MethodAccessor objects
        // among Method objects which refer to the same underlying
        // method in the VM. (All of this contortion is only necessary
        // because of the "accessibility" bit in AccessibleObject,
        // which implicitly requires that new java.lang.reflect
        // objects be fabricated for each reflective call on Class
        // objects.)
        if (this.root != null)
            throw new IllegalArgumentException("Can not copy a non-root Method");

        Method res = new Method(clazz, name, parameterTypes, returnType,
                                exceptionTypes, modifiers, slot, signature,
                                annotations, parameterAnnotations, annotationDefault);
        res.root = this;
        // Might as well eagerly propagate this if already present
        res.methodAccessor = methodAccessor;
        return res;
    }

    
Make a copy of a leaf method.

/**
     * Make a copy of a leaf method.
     */
    Method leafCopy() {
        if (this.root == null)
            throw new IllegalArgumentException("Can only leafCopy a non-root Method");

        Method res = new Method(clazz, name, parameterTypes, returnType,
                exceptionTypes, modifiers, slot, signature,
                annotations, parameterAnnotations, annotationDefault);
        res.root = root;
        res.methodAccessor = methodAccessor;
        return res;
    }

    
Throws:
/**
     * @throws InaccessibleObjectException {@inheritDoc}
     * @throws SecurityException {@inheritDoc}
     */
    @Override
    @CallerSensitive
    public void setAccessible(boolean flag) {
        AccessibleObject.checkPermission();
        if (flag) checkCanSetAccessible(Reflection.getCallerClass());
        setAccessible0(flag);
    }

    @Override
    void checkCanSetAccessible(Class<?> caller) {
        checkCanSetAccessible(caller, clazz);
    }

    @Override
    Method getRoot() {
        return root;
    }

    @Override
    boolean hasGenericInformation() {
        return (getGenericSignature() != null);
    }

    @Override
    byte[] getAnnotationBytes() {
        return annotations;
    }

    
Returns the Class object representing the class or interface that declares the method represented by this object. 
/**
     * Returns the {@code Class} object representing the class or interface
     * that declares the method represented by this object.
     */
    @Override
    public Class<?> getDeclaringClass() {
        return clazz;
    }

    
Returns the name of the method represented by this Method object, as a String. 
/**
     * Returns the name of the method represented by this {@code Method}
     * object, as a {@code String}.
     */
    @Override
    public String getName() {
        return name;
    }

    
{@inheritDoc}

/**
     * {@inheritDoc}
     */
    @Override
    public int getModifiers() {
        return modifiers;
    }

    
{@inheritDoc}

Throws:
Since:1.5
/**
     * {@inheritDoc}
     * @throws GenericSignatureFormatError {@inheritDoc}
     * @since 1.5
     */
    @Override
    @SuppressWarnings({"rawtypes", "unchecked"})
    public TypeVariable<Method>[] getTypeParameters() {
        if (getGenericSignature() != null)
            return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();
        else
            return (TypeVariable<Method>[])new TypeVariable[0];
    }

    
Returns a Class object that represents the formal return type of the method represented by this Method object. 
Returns:the return type for the method this object represents
/**
     * Returns a {@code Class} object that represents the formal return type
     * of the method represented by this {@code Method} object.
     *
     * @return the return type for the method this object represents
     */
    public Class<?> getReturnType() {
        return returnType;
    }

    
Returns a Type object that represents the formal return type of the method represented by this Method object. 
If the return type is a parameterized type, the Type object returned must accurately reflect the actual type parameters used in the source code. 
If the return type is a type variable or a parameterized type, it
is created. Otherwise, it is resolved.

Throws:
Returns: a Type object that represents the formal return type of the underlying method
Since:1.5
/**
     * Returns a {@code Type} object that represents the formal return
     * type of the method represented by this {@code Method} object.
     *
     * <p>If the return type is a parameterized type,
     * the {@code Type} object returned must accurately reflect
     * the actual type parameters used in the source code.
     *
     * <p>If the return type is a type variable or a parameterized type, it
     * is created. Otherwise, it is resolved.
     *
     * @return  a {@code Type} object that represents the formal return
     *     type of the underlying  method
     * @throws GenericSignatureFormatError
     *     if the generic method signature does not conform to the format
     *     specified in
     *     <cite>The Java&trade; Virtual Machine Specification</cite>
     * @throws TypeNotPresentException if the underlying method's
     *     return type refers to a non-existent type declaration
     * @throws MalformedParameterizedTypeException if the
     *     underlying method's return typed refers to a parameterized
     *     type that cannot be instantiated for any reason
     * @since 1.5
     */
    public Type getGenericReturnType() {
      if (getGenericSignature() != null) {
        return getGenericInfo().getReturnType();
      } else { return getReturnType();}
    }

    @Override
    Class<?>[] getSharedParameterTypes() {
        return parameterTypes;
    }

    @Override
    Class<?>[] getSharedExceptionTypes() {
        return exceptionTypes;
    }

    
{@inheritDoc}

/**
     * {@inheritDoc}
     */
    @Override
    public Class<?>[] getParameterTypes() {
        return parameterTypes.clone();
    }

    
{@inheritDoc}

Since:1.8
/**
     * {@inheritDoc}
     * @since 1.8
     */
    public int getParameterCount() { return parameterTypes.length; }


    
{@inheritDoc}

Throws:
Since:1.5
/**
     * {@inheritDoc}
     * @throws GenericSignatureFormatError {@inheritDoc}
     * @throws TypeNotPresentException {@inheritDoc}
     * @throws MalformedParameterizedTypeException {@inheritDoc}
     * @since 1.5
     */
    @Override
    public Type[] getGenericParameterTypes() {
        return super.getGenericParameterTypes();
    }

    
{@inheritDoc}

/**
     * {@inheritDoc}
     */
    @Override
    public Class<?>[] getExceptionTypes() {
        return exceptionTypes.clone();
    }

    
{@inheritDoc}

Throws:
Since:1.5
/**
     * {@inheritDoc}
     * @throws GenericSignatureFormatError {@inheritDoc}
     * @throws TypeNotPresentException {@inheritDoc}
     * @throws MalformedParameterizedTypeException {@inheritDoc}
     * @since 1.5
     */
    @Override
    public Type[] getGenericExceptionTypes() {
        return super.getGenericExceptionTypes();
    }

    
Compares this Method against the specified object. Returns true if the objects are the same. Two Methods are the same if they were declared by the same class and have the same name and formal parameter types and return type. 
/**
     * Compares this {@code Method} against the specified object.  Returns
     * true if the objects are the same.  Two {@code Methods} are the same if
     * they were declared by the same class and have the same name
     * and formal parameter types and return type.
     */
    public boolean equals(Object obj) {
        if (obj != null && obj instanceof Method) {
            Method other = (Method)obj;
            if ((getDeclaringClass() == other.getDeclaringClass())
                && (getName() == other.getName())) {
                if (!returnType.equals(other.getReturnType()))
                    return false;
                return equalParamTypes(parameterTypes, other.parameterTypes);
            }
        }
        return false;
    }

    
Returns a hashcode for this Method. The hashcode is computed as the exclusive-or of the hashcodes for the underlying method's declaring class name and the method's name. 
/**
     * Returns a hashcode for this {@code Method}.  The hashcode is computed
     * as the exclusive-or of the hashcodes for the underlying
     * method's declaring class name and the method's name.
     */
    public int hashCode() {
        return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
    }

    
Returns a string describing this Method. The string is formatted as the method access modifiers, if any, followed by the method return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's formal parameter types. If the method throws checked exceptions, the parameter list is followed by a space, followed by the word "throws" followed by a comma-separated list of the thrown exception types. For example: 
   public boolean java.lang.Object.equals(java.lang.Object)



The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, default, static, final, synchronized, native, strictfp. 
Returns:a string describing this Method
@jls8.4.3 Method Modifiers
@jls9.4   Method Declarations
@jls9.6.1 Annotation Type Elements
/**
     * Returns a string describing this {@code Method}.  The string is
     * formatted as the method access modifiers, if any, followed by
     * the method return type, followed by a space, followed by the
     * class declaring the method, followed by a period, followed by
     * the method name, followed by a parenthesized, comma-separated
     * list of the method's formal parameter types. If the method
     * throws checked exceptions, the parameter list is followed by a
     * space, followed by the word "{@code throws}" followed by a
     * comma-separated list of the thrown exception types.
     * For example:
     * <pre>
     *    public boolean java.lang.Object.equals(java.lang.Object)
     * </pre>
     *
     * <p>The access modifiers are placed in canonical order as
     * specified by "The Java Language Specification".  This is
     * {@code public}, {@code protected} or {@code private} first,
     * and then other modifiers in the following order:
     * {@code abstract}, {@code default}, {@code static}, {@code final},
     * {@code synchronized}, {@code native}, {@code strictfp}.
     *
     * @return a string describing this {@code Method}
     *
     * @jls 8.4.3 Method Modifiers
     * @jls 9.4   Method Declarations
     * @jls 9.6.1 Annotation Type Elements
     */
    public String toString() {
        return sharedToString(Modifier.methodModifiers(),
                              isDefault(),
                              parameterTypes,
                              exceptionTypes);
    }

    @Override
    void specificToStringHeader(StringBuilder sb) {
        sb.append(getReturnType().getTypeName()).append(' ');
        sb.append(getDeclaringClass().getTypeName()).append('.');
        sb.append(getName());
    }

    @Override
    String toShortString() {
        StringBuilder sb = new StringBuilder("method ");
        sb.append(getDeclaringClass().getTypeName()).append('.');
        sb.append(getName());
        sb.append('(');
        StringJoiner sj = new StringJoiner(",");
        for (Class<?> parameterType : getParameterTypes()) {
            sj.add(parameterType.getTypeName());
        }
        sb.append(sj);
        sb.append(')');
        return sb.toString();
    }

    
Returns a string describing this Method, including type parameters. The string is formatted as the method access modifiers, if any, followed by an angle-bracketed comma-separated list of the method's type parameters, if any, followed by the method's generic return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's generic formal parameter types. If this method was declared to take a variable number of arguments, instead of denoting the last parameter as "Type[]", it is denoted as
"Type...". A space is used to separate access modifiers from one another and from the type parameters or return type. If there are no type parameters, the type parameter list is elided; if the type parameter list is present, a space separates the list from the class name. If the method is declared to throw exceptions, the parameter list is followed by a space, followed by the word "throws" followed by a comma-separated list of the generic thrown exception types. 
The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is public, protected or private first, and then other modifiers in the following order: abstract, default, static, final, synchronized, native, strictfp. 
Returns:a string describing this Method, include type parameters
Since:1.5
@jls8.4.3 Method Modifiers
@jls9.4   Method Declarations
@jls9.6.1 Annotation Type Elements
/**
     * Returns a string describing this {@code Method}, including
     * type parameters.  The string is formatted as the method access
     * modifiers, if any, followed by an angle-bracketed
     * comma-separated list of the method's type parameters, if any,
     * followed by the method's generic return type, followed by a
     * space, followed by the class declaring the method, followed by
     * a period, followed by the method name, followed by a
     * parenthesized, comma-separated list of the method's generic
     * formal parameter types.
     *
     * If this method was declared to take a variable number of
     * arguments, instead of denoting the last parameter as
     * "<code><i>Type</i>[]</code>", it is denoted as
     * "<code><i>Type</i>...</code>".
     *
     * A space is used to separate access modifiers from one another
     * and from the type parameters or return type.  If there are no
     * type parameters, the type parameter list is elided; if the type
     * parameter list is present, a space separates the list from the
     * class name.  If the method is declared to throw exceptions, the
     * parameter list is followed by a space, followed by the word
     * "{@code throws}" followed by a comma-separated list of the generic
     * thrown exception types.
     *
     * <p>The access modifiers are placed in canonical order as
     * specified by "The Java Language Specification".  This is
     * {@code public}, {@code protected} or {@code private} first,
     * and then other modifiers in the following order:
     * {@code abstract}, {@code default}, {@code static}, {@code final},
     * {@code synchronized}, {@code native}, {@code strictfp}.
     *
     * @return a string describing this {@code Method},
     * include type parameters
     *
     * @since 1.5
     *
     * @jls 8.4.3 Method Modifiers
     * @jls 9.4   Method Declarations
     * @jls 9.6.1 Annotation Type Elements
     */
    @Override
    public String toGenericString() {
        return sharedToGenericString(Modifier.methodModifiers(), isDefault());
    }

    @Override
    void specificToGenericStringHeader(StringBuilder sb) {
        Type genRetType = getGenericReturnType();
        sb.append(genRetType.getTypeName()).append(' ');
        sb.append(getDeclaringClass().getTypeName()).append('.');
        sb.append(getName());
    }

    
Invokes the underlying method represented by this Method object, on the specified object with the specified parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary. 
If the underlying method is static, then the specified obj argument is ignored. It may be null. 
If the number of formal parameters required by the underlying method is 0, the supplied args array may be of length 0 or null. 
If the underlying method is an instance method, it is invoked
using dynamic method lookup as documented in The Java Language
Specification, section 15.12.4.4; in particular,
overriding based on the runtime type of the target object may occur.

If the underlying method is static, the class that declared
the method is initialized if it has not already been initialized.

If the method completes normally, the value it returns is
returned to the caller of invoke; if the value has a primitive
type, it is first appropriately wrapped in an object. However,
if the value has the type of an array of a primitive type, the
elements of the array are not wrapped in objects; in
other words, an array of primitive type is returned.  If the
underlying method return type is void, the invocation returns
null.

Params:
  • obj –  the object the underlying method is invoked from
  • args – the arguments used for the method call
Throws:
  • IllegalAccessException –  if this Method object is enforcing Java language access control and the underlying method is inaccessible.
  • IllegalArgumentException –  if the method is an
             instance method and the specified object argument
             is not an instance of the class or interface
             declaring the underlying method (or of a subclass
             or implementor thereof); if the number of actual
             and formal parameters differ; if an unwrapping
             conversion for primitive arguments fails; or if,
             after possible unwrapping, a parameter value
             cannot be converted to the corresponding formal
             parameter type by a method invocation conversion.
  • InvocationTargetException – if the underlying method
             throws an exception.
  • NullPointerException –      if the specified object is null
             and the method is an instance method.
  • ExceptionInInitializerError – if the initialization
provoked by this method fails.
Returns:the result of dispatching the method represented by this object on obj with parameters args
/**
     * Invokes the underlying method represented by this {@code Method}
     * object, on the specified object with the specified parameters.
     * Individual parameters are automatically unwrapped to match
     * primitive formal parameters, and both primitive and reference
     * parameters are subject to method invocation conversions as
     * necessary.
     *
     * <p>If the underlying method is static, then the specified {@code obj}
     * argument is ignored. It may be null.
     *
     * <p>If the number of formal parameters required by the underlying method is
     * 0, the supplied {@code args} array may be of length 0 or null.
     *
     * <p>If the underlying method is an instance method, it is invoked
     * using dynamic method lookup as documented in The Java Language
     * Specification, section 15.12.4.4; in particular,
     * overriding based on the runtime type of the target object may occur.
     *
     * <p>If the underlying method is static, the class that declared
     * the method is initialized if it has not already been initialized.
     *
     * <p>If the method completes normally, the value it returns is
     * returned to the caller of invoke; if the value has a primitive
     * type, it is first appropriately wrapped in an object. However,
     * if the value has the type of an array of a primitive type, the
     * elements of the array are <i>not</i> wrapped in objects; in
     * other words, an array of primitive type is returned.  If the
     * underlying method return type is void, the invocation returns
     * null.
     *
     * @param obj  the object the underlying method is invoked from
     * @param args the arguments used for the method call
     * @return the result of dispatching the method represented by
     * this object on {@code obj} with parameters
     * {@code args}
     *
     * @exception IllegalAccessException    if this {@code Method} object
     *              is enforcing Java language access control and the underlying
     *              method is inaccessible.
     * @exception IllegalArgumentException  if the method is an
     *              instance method and the specified object argument
     *              is not an instance of the class or interface
     *              declaring the underlying method (or of a subclass
     *              or implementor thereof); if the number of actual
     *              and formal parameters differ; if an unwrapping
     *              conversion for primitive arguments fails; or if,
     *              after possible unwrapping, a parameter value
     *              cannot be converted to the corresponding formal
     *              parameter type by a method invocation conversion.
     * @exception InvocationTargetException if the underlying method
     *              throws an exception.
     * @exception NullPointerException      if the specified object is null
     *              and the method is an instance method.
     * @exception ExceptionInInitializerError if the initialization
     * provoked by this method fails.
     */
    @CallerSensitive
    @ForceInline // to ensure Reflection.getCallerClass optimization
    @HotSpotIntrinsicCandidate
    public Object invoke(Object obj, Object... args)
        throws IllegalAccessException, IllegalArgumentException,
           InvocationTargetException
    {
        if (!override) {
            Class<?> caller = Reflection.getCallerClass();
            checkAccess(caller, clazz,
                        Modifier.isStatic(modifiers) ? null : obj.getClass(),
                        modifiers);
        }
        MethodAccessor ma = methodAccessor;             // read volatile
        if (ma == null) {
            ma = acquireMethodAccessor();
        }
        return ma.invoke(obj, args);
    }

    
Returns true if this method is a bridge method; returns false otherwise. 
Returns:true if and only if this method is a bridge
method as defined by the Java Language Specification.
Since:1.5
/**
     * Returns {@code true} if this method is a bridge
     * method; returns {@code false} otherwise.
     *
     * @return true if and only if this method is a bridge
     * method as defined by the Java Language Specification.
     * @since 1.5
     */
    public boolean isBridge() {
        return (getModifiers() & Modifier.BRIDGE) != 0;
    }

    
{@inheritDoc}

Since:1.5
/**
     * {@inheritDoc}
     * @since 1.5
     */
    @Override
    public boolean isVarArgs() {
        return super.isVarArgs();
    }

    
{@inheritDoc}

@jls13.1 The Form of a Binary
Since:1.5
/**
     * {@inheritDoc}
     * @jls 13.1 The Form of a Binary
     * @since 1.5
     */
    @Override
    public boolean isSynthetic() {
        return super.isSynthetic();
    }

    
Returns true if this method is a default method; returns false otherwise. A default method is a public non-abstract instance method, that is, a non-static method with a body, declared in an interface type. 
Returns:true if and only if this method is a default
method as defined by the Java Language Specification.
Since:1.8
/**
     * Returns {@code true} if this method is a default
     * method; returns {@code false} otherwise.
     *
     * A default method is a public non-abstract instance method, that
     * is, a non-static method with a body, declared in an interface
     * type.
     *
     * @return true if and only if this method is a default
     * method as defined by the Java Language Specification.
     * @since 1.8
     */
    public boolean isDefault() {
        // Default methods are public non-abstract instance methods
        // declared in an interface.
        return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
                Modifier.PUBLIC) && getDeclaringClass().isInterface();
    }

    // NOTE that there is no synchronization used here. It is correct
    // (though not efficient) to generate more than one MethodAccessor
    // for a given Method. However, avoiding synchronization will
    // probably make the implementation more scalable.
    private MethodAccessor acquireMethodAccessor() {
        // First check to see if one has been created yet, and take it
        // if so
        MethodAccessor tmp = null;
        if (root != null) tmp = root.getMethodAccessor();
        if (tmp != null) {
            methodAccessor = tmp;
        } else {
            // Otherwise fabricate one and propagate it up to the root
            tmp = reflectionFactory.newMethodAccessor(this);
            setMethodAccessor(tmp);
        }

        return tmp;
    }

    // Returns MethodAccessor for this Method object, not looking up
    // the chain to the root
    MethodAccessor getMethodAccessor() {
        return methodAccessor;
    }

    // Sets the MethodAccessor for this Method object and
    // (recursively) its root
    void setMethodAccessor(MethodAccessor accessor) {
        methodAccessor = accessor;
        // Propagate up
        if (root != null) {
            root.setMethodAccessor(accessor);
        }
    }

    
Returns the default value for the annotation member represented by this Method instance. If the member is of a primitive type, an instance of the corresponding wrapper type is returned. Returns null if no default is associated with the member, or if the method instance does not represent a declared member of an annotation type. 
Throws:
Returns:the default value for the annotation member represented by this Method instance.
Since: 1.5
/**
     * Returns the default value for the annotation member represented by
     * this {@code Method} instance.  If the member is of a primitive type,
     * an instance of the corresponding wrapper type is returned. Returns
     * null if no default is associated with the member, or if the method
     * instance does not represent a declared member of an annotation type.
     *
     * @return the default value for the annotation member represented
     *     by this {@code Method} instance.
     * @throws TypeNotPresentException if the annotation is of type
     *     {@link Class} and no definition can be found for the
     *     default class value.
     * @since  1.5
     */
    public Object getDefaultValue() {
        if  (annotationDefault == null)
            return null;
        Class<?> memberType = AnnotationType.invocationHandlerReturnType(
            getReturnType());
        Object result = AnnotationParser.parseMemberValue(
            memberType, ByteBuffer.wrap(annotationDefault),
            SharedSecrets.getJavaLangAccess().
                getConstantPool(getDeclaringClass()),
            getDeclaringClass());
        if (result instanceof ExceptionProxy) {
            if (result instanceof TypeNotPresentExceptionProxy) {
                TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
                throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
            }
            throw new AnnotationFormatError("Invalid default: " + this);
        }
        return result;
    }

    
{@inheritDoc}

Throws:
Since:1.5
/**
     * {@inheritDoc}
     * @throws NullPointerException  {@inheritDoc}
     * @since 1.5
     */
    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
        return super.getAnnotation(annotationClass);
    }

    
{@inheritDoc}

Since:1.5
/**
     * {@inheritDoc}
     * @since 1.5
     */
    public Annotation[] getDeclaredAnnotations()  {
        return super.getDeclaredAnnotations();
    }

    
{@inheritDoc}

Since:1.5
/**
     * {@inheritDoc}
     * @since 1.5
     */
    @Override
    public Annotation[][] getParameterAnnotations() {
        return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
    }

    
{@inheritDoc}

Since:1.8
/**
     * {@inheritDoc}
     * @since 1.8
     */
    @Override
    public AnnotatedType getAnnotatedReturnType() {
        return getAnnotatedReturnType0(getGenericReturnType());
    }

    @Override
    boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
        throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
    }
}