Reflect 4 Proxy May 2026

import java.lang.reflect.Proxy; public class Main public static void main(String[] args) RealUserService realService = new RealUserService();

Enhancer enhancer = new Enhancer(); enhancer.setSuperclass(RealUserService.class); enhancer.setCallback(new MethodInterceptor() public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable // interceptor logic return proxy.invokeSuper(obj, args); ); RealUserService proxy = (RealUserService) enhancer.create(); The reflect 4 proxy mechanism remains a cornerstone of Java’s dynamic capabilities. Although newer versions of Java introduced features like dynamic proxies via MethodHandles (more lightweight) and inline classes (Project Valhalla), java.lang.reflect.Proxy is still widely used because it is simple, standardized, and deeply integrated into major frameworks. reflect 4 proxy

public class RealUserService implements UserService @Override public String getUserName(int userId) return "User_" + userId; @Override public void updateUser(int userId, String newName) System.out.println("Updated user " + userId + " to " + newName); import java

public LoggingHandler(Object target) this.target = target; Enhancer enhancer = new Enhancer()

public interface InvocationHandler public Object invoke(Object proxy, Method method, Object[] args) throws Throwable;

import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; public class LoggingHandler implements InvocationHandler private final Object target; // real object

UserService proxy = (UserService) Proxy.newProxyInstance( UserService.class.getClassLoader(), new Class[]UserService.class, new LoggingHandler(realService) ); // Call methods via proxy String name = proxy.getUserName(42); proxy.updateUser(42, "John Doe");