The @Required annotation is used to make sure a particular property has been set. If you are migrate your existing project to Spring framework or have your own @Required-style annotation for whatever reasons, Spring is allow you to define your custom @Required-style annotation, which is equivalent to @Required annotation.

In this example, you will create a custom @Required-style annotation named @Mandatory, which is equivalent to @Required annotation.

1. Create the @Mandatory interface

package com.mkyong.common;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.METHOD)public @interface Mandatory {}

2. Apply it to a property

package com.mkyong.common;public class Customer {    private Person person;    private int type;    private String action;        @Mandatory    public void setPerson(Person person) {        this.person = person;    }    //getter and setter methods}

3. Register it

Include your new @Mandatory annotation in ‘RequiredAnnotationBeanPostProcessor’ class.

4. Done

Done, you just created a new custom @Required-style annotation named @Mandatory, which is equivalent to @Required annotation.