jvm七:数组创建本质

package com.atChina.jvm;

/*
*   对于数组实例来说,其类型是由JVM在运行期动态生成的,表示为[Lcom.atChina.jvm.Father4
*   这种方式,动态生成的类型，其父类型就是Object
*
*   对于数组来说,JavaDoc经常将构成数组的元素称为Component,实际上就是将数组降低一个维度的类型
*
*   助记符:
*       anewarray:表示创建一个引用类型(如类,接口,数组)的数组,并将其引用值压入栈顶
*        newarray:表示创建一个指定的基本类型(如int, float,char等)的数组,并将其引用值压入栈顶
*/
public class Test4 {
    public static void main(String[] args) {

        Father4[] f = new Father4[2];
        System.out.println(f.getClass());
        System.out.println(f.getClass().getSuperclass());

        int[] ins = new int[3];
        System.out.println(ins.getClass());
        System.out.println(ins.getClass().getSuperclass());
    }
}
class Father4{
    static{
        System.out.println("桃园结义");
    }
}

 

使用 javap -c 类路径.类名 反编译下类

javap -c com.atChina.jvm.Test4
Compiled from "Test4.java"
public class com.atChina.jvm.Test4 extends java.lang.Object{
public com.atChina.jvm.Test4();
  Code:
   0:   aload_0
   1:   invokespecial   #1; //Method java/lang/Object."":()V
   4:   return

public static void main(java.lang.String[]);
  Code:
   0:   iconst_2
   1:   anewarray       #2; //class com/atChina/jvm/Father4
   4:   astore_1
   5:   getstatic       #3; //Field java/lang/System.out:Ljava/io/PrintStream;
   8:   aload_1
   9:   invokevirtual   #4; //Method java/lang/Object.getClass:()Ljava/lang/Class;
   12:  invokevirtual   #5; //Method java/io/PrintStream.println:(Ljava/lang/Object;)V
   15:  getstatic       #3; //Field java/lang/System.out:Ljava/io/PrintStream;
   18:  aload_1
   19:  invokevirtual   #4; //Method java/lang/Object.getClass:()Ljava/lang/Class;
   22:  invokevirtual   #6; //Method java/lang/Class.getSuperclass:()Ljava/lang/Class;
   25:  invokevirtual   #5; //Method java/io/PrintStream.println:(Ljava/lang/Object;)V
   28:  iconst_3
   29:  newarray int
   31:  astore_2
   32:  getstatic       #3; //Field java/lang/System.out:Ljava/io/PrintStream;
   35:  aload_2
   36:  invokevirtual   #4; //Method java/lang/Object.getClass:()Ljava/lang/Class;
   39:  invokevirtual   #5; //Method java/io/PrintStream.println:(Ljava/lang/Object;)V
   42:  getstatic       #3; //Field java/lang/System.out:Ljava/io/PrintStream;
   45:  aload_2
   46:  invokevirtual   #4; //Method java/lang/Object.getClass:()Ljava/lang/Class;
   49:  invokevirtual   #6; //Method java/lang/Class.getSuperclass:()Ljava/lang/Class;
   52:  invokevirtual   #5; //Method java/io/PrintStream.println:(Ljava/lang/Object;)V
   55:  return

}