Load order of classes in Java (GO)

1. When the virtual machine loads the Java class for the first time, it initializes the static initialization block, the static member variable, and the static method once.
2. An instance of the class is created only when the new method is called
3, the class instance creation process: Initializes according to the parent-child inheritance relation, first executes the initialization block part of the parents, then constructs the method of the parent class, then executes the initialization block of the subclass that inherits from this class, and finally the constructor method of the subclass
4, when the class instance destroys, first destroys the subclass part, then destroys the parent class part

public class parent{public    static int t = PARENTSTATICMETHOD2 ();    {        System.out.println ("Parent class non-static initialization block");    }    Static    {        System.out.println ("The parent class statically initializes the Block");    }    Public parent ()    {        System.out.println ("constructor method for parent class");    }    public static int Parentstaticmethod ()    {        System.out.println ("static method of the parent class class");        return ten;    }    public static int parentStaticMethod2 ()    {        System.out.println ("static method 2 of the parent class");        return 9;    }      @Override    protected void Finalize () throws Throwable    {        //TODO auto-generated method stub        Super.finalize ();        System.out.println ("Destroy parent Class");    }    }

public class Child extends parent{    {        System.out.println ("Subclass non-static initialization block");    }    Static    {        System.out.println ("Subclass static initialization Block");    }    Public Child ()    {        System.out.println ("constructor method for subclasses");    }    public static int Childstaticmethod ()    {        System.out.println ("static method of the subclass");        return;    }    @Override    protected void Finalize () throws Throwable    {        //TODO auto-generated method stub        Super.finalize ();        SYSTEM.OUT.PRINTLN ("Destroy sub-Class");}    }

public class test{public       static void Main (string[] args)    {        //TODO auto-generated method stub        Parent.parentstaticmethod ();//child Child        = new Child ();}            }

Output

static method for parent class 2 static method of parent class static initialization block parent class class

The static method in the class is loaded on the first call, and the static members in the class are loaded in the order in which they appear in the class. When calling static Method 2 o'clock output

static method for parent class 2 static method for parent class static initialization block parent Class 2

Comment out Parent.parentstaticmethod ();

Remove the comment child child = new Child ();

static method of parent Class 2 parent class static initialization block subclass static initialization block parent class non-static initialization block parent class constructor method for subclass non-static initialization block sub-class

Guoyuqiangf8 not accumulate Kuibu, not even thousands of miles. Loading order of classes in Java

1. When the virtual machine loads the Java class for the first time, it initializes the static initialization block, the static member variable, and the static method once.
2. An instance of the class is created only when the new method is called
3, the class instance creation process: Initializes according to the parent-child inheritance relation, first executes the initialization block part of the parents, then constructs the method of the parent class, then executes the initialization block of the subclass that inherits from this class, and finally the constructor method of the subclass
4, when the class instance destroys, first destroys the subclass part, then destroys the parent class part

public class parent{public    static int t = PARENTSTATICMETHOD2 ();    {        System.out.println ("Parent class non-static initialization block");    }    Static    {        System.out.println ("The parent class statically initializes the Block");    }    Public parent ()    {        System.out.println ("constructor method for parent class");    }    public static int Parentstaticmethod ()    {        System.out.println ("static method of the parent class class");        return ten;    }    public static int parentStaticMethod2 ()    {        System.out.println ("static method 2 of the parent class");        return 9;    }      @Override    protected void Finalize () throws Throwable    {        //TODO auto-generated method stub        Super.finalize ();        System.out.println ("Destroy parent Class");    }    }

public class Child extends parent{    {        System.out.println ("Subclass non-static initialization block");    }    Static    {        System.out.println ("Subclass static initialization Block");    }    Public Child ()    {        System.out.println ("constructor method for subclasses");    }    public static int Childstaticmethod ()    {        System.out.println ("static method of the subclass");        return;    }    @Override    protected void Finalize () throws Throwable    {        //TODO auto-generated method stub        Super.finalize ();        SYSTEM.OUT.PRINTLN ("Destroy sub-Class");}    }

public class test{public       static void Main (string[] args)    {        //TODO auto-generated method stub        Parent.parentstaticmethod ();//child Child        = new Child ();}            }

Output

static method for parent class 2 static method of parent class static initialization block parent class class

The static method in the class is loaded on the first call, and the static members in the class are loaded in the order in which they appear in the class. When calling static Method 2 o'clock output

static method for parent class 2 static method for parent class static initialization block parent Class 2

Comment out Parent.parentstaticmethod ();

Remove the comment child child = new Child ();

static method of parent Class 2 parent class static initialization block subclass static initialization block parent class non-static initialization block parent class constructor method for subclass non-static initialization block sub-class

Category: Java Foundation Green Channel: Good text to top attention my collection This article contact me Assassin XIII
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Posted on 2012-10-31 23:28 Assassin XIII Read (9090) Comments (2) Edit Collection

Reviews # F2013-08-28 17:20 Quiet * diligent

The first time a Java class is loaded, a static member variable or method is initialized once, but the method is not invoked, and the static member variable is the same level as the static initialization block, and the non-static member variable and the non-static initialization block level are the same.

Initialize the static code of the parent class first---> Initialize the subclass's static code--
Initializes the non-static code of the parent class---> initializes the parent class constructor--->
Initialize subclass non-static code---> Initialize subclass constructor http://www.cnblogs.com/guoyuqiangf8/archive/2012/10/31/2748909.html

Load order of classes in Java (GO)