CGLIB

<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>2.2.2</version>
</dependency>

public class SampleClass {
    public void test(){
        System.out.println("hello world");
    }

    public static void main(String[] args) {
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(SampleClass.class);
        enhancer.setCallback(new MethodInterceptor() {
            @Override
            public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
                System.out.println("before method run...");
                Object result = proxy.invokeSuper(obj, args);
                System.out.println("after method run...");
                return result;
            }
        });
        SampleClass sample = (SampleClass) enhancer.create();
        sample.test();
    }
}



public class SampleClass {
    public String test(String input){
        return "hello world";
    }
}