1、创建数组
创建一个MyParent4[] 数组
public class MyTest4 {
public static void main(String[] args) {
MyParent4[] myParent4s = new MyParent4[1];
System.out.println(myParent4s.getClass());
}
}
class MyParent4{
static {
System.out.println("MyParent4 static block");
}
}
打印结构

说明此处并不符合主动使用的场景,所有不会初始化MyParent4。 打印myParent4s.getClass()的结果为数组类型。[Lcom.example.jvm.classloader.MyParent4 这个类型是JVM在运行期创建出来的。
2、完整的创建数组代码
public class MyTest4 {
public static void main(String[] args) {
MyParent4[] myParent4s = new MyParent4[1];
System.out.println(myParent4s.getClass());
MyParent4[][] myParent4s1 = new MyParent4[1][1];
System.out.println(myParent4s1.getClass());
System.out.println(myParent4s.getClass().getSuperclass());
System.out.println(myParent4s1.getClass().getSuperclass());
int[] ints = new int[1];
System.out.println(ints.getClass());
System.out.println(ints.getClass().getSuperclass());
}
}
class MyParent4{
static {
System.out.println("MyParent4 static block");
}
}
打印结果
class [Lcom.example.jvm.classloader.MyParent4; class [[Lcom.example.jvm.classloader.MyParent4; class java.lang.Object class java.lang.Object class [I class java.lang.Object
反编译
Compiled from "MyTest4.java"
public class com.example.jvm.classloader.MyTest4 {
public com.example.jvm.classloader.MyTest4();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
public static void main(java.lang.String[]);
Code:
0: iconst_1
1: anewarray #2 // class com/example/jvm/classloader/MyParent4
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: iconst_1
16: iconst_1
17: multianewarray #6, 2 // class "[[Lcom/example/jvm/classloader/MyParent4;"
21: astore_2
22: getstatic #3 // Field java/lang/System.out:Ljava/io/PrintStream;
25: aload_2
26: invokevirtual #4 // Method java/lang/Object.getClass:()Ljava/lang/Class;
29: invokevirtual #5 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
32: getstatic #3 // Field java/lang/System.out:Ljava/io/PrintStream;
35: aload_1
36: invokevirtual #4 // Method java/lang/Object.getClass:()Ljava/lang/Class;
39: invokevirtual #7 // Method java/lang/Class.getSuperclass:()Ljava/lang/Class;
42: invokevirtual #5 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
45: getstatic #3 // Field java/lang/System.out:Ljava/io/PrintStream;
48: aload_2
49: invokevirtual #4 // Method java/lang/Object.getClass:()Ljava/lang/Class;
52: invokevirtual #7 // Method java/lang/Class.getSuperclass:()Ljava/lang/Class;
55: invokevirtual #5 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
58: iconst_1
59: newarray int
61: astore_3
62: getstatic #3 // Field java/lang/System.out:Ljava/io/PrintStream;
65: aload_3
66: invokevirtual #4 // Method java/lang/Object.getClass:()Ljava/lang/Class;
69: invokevirtual #5 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
72: getstatic #3 // Field java/lang/System.out:Ljava/io/PrintStream;
75: aload_3
76: invokevirtual #4 // Method java/lang/Object.getClass:()Ljava/lang/Class;
79: invokevirtual #7 // Method java/lang/Class.getSuperclass:()Ljava/lang/Class;
82: invokevirtual #5 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
85: return
}
助记符:
anewarray: 表示创建一个引用类型的(如类、接口、数组)数组,并将其引用值压如栈顶 (1: anewarray #2)
newarray: 表示创建一个指定的原始类型(如int,float,char等)的数组,并将其引用值压入栈顶 ( 59: newarray int)
原文:https://www.cnblogs.com/linlf03/p/10990145.html