Java Annotation basics

TestAnnotation.java

/*
 * Basic usage of Java annotation 
 */

package test.another;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;

public class TestAnnotation {
	
	@AnnotInfo(id=13143, info="An ordinary method")
	public void operate(){
		System.out.println("operating");
	}
	
	public static void main(String[] args) {
		Method[] methods = TestAnnotation.class.getDeclaredMethods();
		for (Method method : methods) {
			AnnotInfo annot = method.getAnnotation(AnnotInfo.class);
			if(annot!=null){
				System.out.println(method.getName()+" has the annotation: " 
						+annot.getClass().getName()+" "
						+annot.id()+"/"+annot.info());
			}
		}
	}

}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@interface AnnotInfo{
	int id() default 0; // Must NOT contains parameters or throws exception
	String info();
}