记录个jhsdb存在的问题

源码

//应用类，含有main()方法
public class Application {
    //静态方法
    public static void main(String[] args) {

        // 实例化一个类对象
        Studen p = new Studen(1,21,"张三");

        Application t = new Application();
        System.out.println(t.getClass().getName());

        // 输出类中的实例属性值
        System.out.println("StudenID = " + p.StudenID + ",age = " + p.age + ",name = " + p.name);

        // 输出类中的静态属性值
        System.out.println("classID = " + Studen.classID);

        // 使用p.study()，调用对象p的方法study()，
// 并在方法study()中使用this，那么this将指向对象p。
        p.study();

        // 调用静态方法
        Studen.showClassID("班级ID号是：");

        // 实例化另一个类对象
        Studen p1 = new Studen(1,21,"李斯");

    }
}

class Studen {

    //1、字段
    //1-1 实例字段
    int StudenID;
    int age  = 25;
    String name;

    //1-2 静态字段
    public static int classID = 1;

    //2、方法
    //2-1 实例方法        含有隐式的形参变量 this
//2-1-1 实例构造方法
//编译后的方法：
//public Studen(Studen this,int StudenID,int age,String name){}
    public Studen(int StudenID,int age,String name) {
        this.StudenID = StudenID;
        this.name = name;
        this.age = age;
    }

    //2-1-2 实例方法
//编译后的方法：public void study(Studen this){}
    public void study(){
        Application t = new Application();
        System.out.println(t.getClass().getName());
        int a = 11;
        int b = 22;
        System.out.println(a + b);
        System.out.println(this.name + "正在学习");
    }

    //2-2 静态方法        没有隐式的形参变量 this
    //2-2-1 静态方法
    //编译后的方法：public static void showClassID(){}
    public static void showClassID(String name){
        System.out.println(name + classID);
    }
}

断点打在：System.out.println(a + b);

通过jhsdb查看对应的栈帧布局：

布局示意图

使用mem查看

mem -v 0x00000085d2bff2e8,0x00000085d2bff3b8

Address 0x00000085d2bff2e8: In java stack [0x00000085d2c00000,0x00000085d2bfeaf8,0x00000085d2b00000] for thread sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750:
   "main" #1 prio=5 tid=0x0000023af427d750 nid=16432 at breakpoint [0x00000085d2bff000]
   java.lang.Thread.State: RUNNABLE
   JavaThread state: _thread_blocked
0x00000085d2bff2e8: 0x00000085d2bff2e8 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff2f0: 0x0000023a915010cb
0x00000085d2bff2f8: 0x0000000000000005
0x00000085d2bff300: 0x0000023a915014e0
0x00000085d2bff308: 0x0000000000000000
0x00000085d2bff310: 0x0000023b0c85e448 In unknown section of Java heap
0x00000085d2bff318: 0x0000023a91501120 Method Studen.study()V@0x0000023a91501120
0x00000085d2bff320: 0x0000000000000000
0x00000085d2bff328: 0x00000085d2bff358 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff330: 0x00000085d2bff3a8 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff338: 0x0000023a8753919c In interpreter codelet: return entry points [0x0000023a87538468, 0x0000023a8753a550)  8424 bytes  
0x00000085d2bff340: 0x0000000000000016
0x00000085d2bff348: 0x000000000000000b
0x00000085d2bff350: 0x0000023b0c9fbe40 In unknown section of Java heap
0x00000085d2bff358: 0x0000023b0c85e5a0 In unknown section of Java heap
0x00000085d2bff360: 0x00000085d2bff360 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff368: 0x0000023a91500578
0x00000085d2bff370: 0x0000000000000005
0x00000085d2bff378: 0x0000023a915008b0
0x00000085d2bff380: 0x0000000000000000
0x00000085d2bff388: 0x0000023b0c85c3b8 In unknown section of Java heap
0x00000085d2bff390: 0x0000023a915005d0 Method Application.main([Ljava/lang/String;)V@0x0000023a915005d0
0x00000085d2bff398: 0x00000085d2bff358 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff3a0: 0x00000085d2bff3d0 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff3a8: 0x00000085d2bff5b0 In java stack for thread "main" sun.jvm.hotspot.runtime.JavaThread@0x0000023af427d750
0x00000085d2bff3b0: 0x0000023a87530fff In code in sun.jvm.hotspot.code.BufferBlob@0x0000023a87530e90

问题所在

我就很纳闷按照图中的显示，0x0000000000000016和0x000000000000000b应该在Application.main栈帧中。

Why？

0x0000000000000016和0x000000000000000b应该是Studen.study方法栈帧的一部分啊。

佐证：

javac -g Application.java javap -c Studen

public void study();
    Code:
       0: new           #20                 // class Application
       3: dup
       4: invokespecial #22                 // Method Application."<init>":()V
       7: astore_1
       8: getstatic     #23                 // Field java/lang/System.out:Ljava/io/PrintStream;
      11: aload_1
      12: invokevirtual #29                 // Method java/lang/Object.getClass:()Ljava/lang/Class;
      15: invokevirtual #33                 // Method java/lang/Class.getName:()Ljava/lang/String;
      18: invokevirtual #39                 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      21: bipush        11
      23: istore_2
      24: bipush        22
      26: istore_3
      27: getstatic     #23                 // Field java/lang/System.out:Ljava/io/PrintStream;
      30: iload_2
      31: iload_3
      32: iadd
      33: invokevirtual #45                 // Method java/io/PrintStream.println:(I)V
      36: getstatic     #23                 // Field java/lang/System.out:Ljava/io/PrintStream;
      39: aload_0
      40: getfield      #16                 // Field name:Ljava/lang/String;
      43: invokedynamic #48,  0             // InvokeDynamic #0:makeConcatWithConstants:(Ljava/lang/String;)Ljava/lang/String;
      48: invokevirtual #39                 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
      51: return

Studen.study对应的字节码中bipush 11和bipush 22证明11和22是在study方法中产生的，So，JHSDB 工具的解析或标注存在问题