Is it possible to create a proxy class only from the interface

without the need to create an instance of the class that implements this interface?

The proxy class will be the class that implements the interface. The difference from the implementation of the usual class is that it is created at runtime.

Proxy :

A dynamic proxy class (below the proxy class below). A proxy interface is a proxy class interface. A proxy instance is an instance of a proxy class.

The implementation of all proxy interface methods is defined in an instance of the InvocationHandler class.

For example, I have an interface with 2 methods:

 private interface Foo { void method1(); void method2(); void method3(); } 

I want to create a proxy that implements method1 , and doesn’t do anything to everyone else (or threw an exception that the method is not implemented). This can be done, for example, as follows:

 public static void main(String... arg) { Foo foo = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(), new Class[]{Foo.class}, (proxy, method, args) -> { switch (method.getName()) { case "method1": System.out.println("method1"); return null; default: break; } throw new RuntimeException(method.getName() + " is not implemented"); }); foo.method1(); foo.method2(); } 

Result of performance:

method1
Exception in thread "main" java.lang.RuntimeException: method2 is not implemented ...