Initializer block.

Ref:　　Initializing Fields

　　Instance initializers are permitted to refer to the current object via the keyword this,Ref:　　Instance Initializers

/*
Initializer blocks,have the same capability as 'constructor',that is, they can use to initialze instance members.
We use 'initialzer blocks',because all the instances of the class can have the same characteristic,such as 'cry'.
*/
package kju.obj;

import static kju.print.Printer.*;
class InitializerBlock {
    public static void main(String[] args) {
        Person p = new Person();
        Person lily = new Person("Lily", 21);
        printHr();
        lily.cry();
        /*prints begin:
        name = null is crying
        name = null is crying

        -----------------------------------
        name = Lily is crying
        :prints ends*/
    }
}

class Person {
    {
        cry();
    }

    public Person() {
        
    }

    public Person(String name) {
        this.name = name;
    }

    public Person(String name, int age) {
        this(name);
        this.age = age;
    }

    public void cry() {
        println("name = " + name + " is crying");
    }

    private String name;
    private int age;
}