What is Retention policy in java annotations?

• A retention policy determines at what point annotation should be discarded.
• Java defined 3 types of retention policies through java.lang.annotation.RetentionPolicy enumeration. It has SOURCE, CLASS and RUNTIME.
• Annotation with retention policy SOURCE will be retained only with source code, and discarded during compile time.
• Annotation with retention policy CLASS will be retained till compiling the code, and discarded during runtime.
• Annotation with retention policy RUNTIME will be available to the JVM through runtime.
• The retention policy will be specified by using java built-in annotation @Retention, and we have to pass the retention policy type.
• The default retention policy type is CLASS.

package com.java2novice.annotations;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Retention(RetentionPolicy.RUNTIME)
public @interface MySampleAnn {

	String name();
	String desc();
}

class MyAnnTest{
	
	@MySampleAnn(name = "test1", desc = "testing annotations")
	public void myTestMethod(){
		//method implementation
	}
}