With this example we are going to demonstrate how to create a Proxy object. A proxy is a class functioning as an interface to a network connection, a large object in memory, a file, or some other resource that is expensive or impossible to duplicate. In short, to create a Proxy object we have followed the steps below:

• We have created an interface,MyInterface with a method and the implementation of the interface,MyInterfaceImpl.
• We have createdMyProxy class,that implements theInvocationHandler. It has anObject o and a constructor where it initializes its object. It also has a method,Object invoke(Object proxy, Method m, Object[] args), that usesinvoke(Object obj, Object... args) API method ofMethod to get the underlying method represented by this Method object, on the specified object with the specified parameters and returns this result.
• We create an instance of a proxy class for the specified interface that dispatches method invocations to the specified invocation handler, usingnewProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h) API method ofProxy.
• Then we invoke the method of the object.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;import java.lang.reflect.InvocationHandler;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.lang.reflect.Proxy;public class CreateProxyObject {public static void main(String[] args) {// return an instance of a proxy class for the specified interfaces    // that dispatches method invocations to the specified invocation handlerMyInterface myintf = (MyInterface)Proxy.newProxyInstance(    MyInterface.class.getClassLoader(),    new Class[]{MyInterface.class},    new MyProxy(new MyInterfaceImpl()));// Invoke the methodmyintf.method();}private static interface MyInterface {    void method();}private static class MyInterfaceImpl implements MyInterface {    public void method() {    System.out.println("Plain method is invoked");    }}private static class MyProxy implements InvocationHandler {    Object obj;    public MyProxy(Object o) {  obj = o;    }    public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {      Object result = null;   try {System.out.println("Proxy Class is called before method invocation");result = m.invoke(obj, args);  }  catch (InvocationTargetException e) {  System.out.println("Invocation Target Exception: " + e);  }  catch (Exception e) {  System.out.println("Invocation Target Exception: " + e);  }  finally {  System.out.println("Proxy Class is called after method invocation");  }  return result;      }    }}

Output:

Proxy Class is called before method invocationPlain method is invokedProxy Class is called after method invocation

 
This was an example of how to create a Proxy object in Java.

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