Java Interview Basics------"Parent-child class static code block in Java, code block, construction method execution order

4 , indicating the running result of the following program.

Class A {

static {

System.out.print ("1");

}

Public A () {

System.out.print ("2");

}

}

Class B extends a{

static {

System.out.print ("a");

}

Public B () {

System.out.print ("B");

}

}

public class Hello {

public static void Main (string[] args) {

A ab = new B ();

AB = new B ();

}

}

A: Execution result: 1a2b2b. When you create an object, the constructor is called in the order that it initializes the static member, then calls the parent class constructor, initializes the non-static member, and finally calls itself the constructor.

The following demo:

Parent.java

/** * @author: Snowing * @date  : April 18, 2017 *  */public class Parent {static {        System.out.println ("Parent ' s static code block ");    }        {        System.out.println ("Parent ' s code block");    }        Public parent () {        System.out.println ("Parent ' s constructor method");}    }

Child.java

/** * @author: Snowing * @date  : April 18, 2017 *  */public class Child extends Parent{static {        System.out.print ln ("Child ' s Static code block");    }        {        System.out.println ("Child ' s code block");    }        Public Child () {        System.out.println ("child ' s construction method");    }    public static void Main (string[] args) {    new Child ()}}

Output:

Java Interview Basics------"Parent-child class static code block in Java, code block, construction method execution order