Math math=new Math();
math.compute();//調(diào)用實例方法compute（）

D:\wyonline\myworkspaces\framework\Test\bin\com\wkp\jvm>javap
用法: javap <options> <classes>
其中, 可能的選項包括:
  -help  --help  -?        輸出此用法消息
  -version                 版本信息
  -v  -verbose             輸出附加信息
  -l                       輸出行號和本地變量表
  -public                  僅顯示公共類和成員
  -protected               顯示受保護的/公共類和成員
  -package                 顯示程序包/受保護的/公共類
                           和成員 (默認)
  -p  -private             顯示所有類和成員
  -c                       對代碼進行反匯編
  -s                       輸出內(nèi)部類型簽名
  -sysinfo                 顯示正在處理的類的
                           系統(tǒng)信息 (路徑, 大小, 日期, MD5 散列)
  -constants               顯示最終常量
  -classpath <path>        指定查找用戶類文件的位置
  -cp <path>               指定查找用戶類文件的位置
  -bootclasspath <path>    覆蓋引導(dǎo)類文件的位置

package com.wkp.jvm;
 
public class Math {
 
	public static final Integer CONSTANT=666;
	
	public int compute() {//一個方法對應(yīng)一塊棧幀內(nèi)存區(qū)域
		int a=3;
		int b=5;
		int c=(a+b)*10;
		return c;
	}
	
	public static void main(String[] args) {
		Math math=new Math();
		math.compute();
	}
}

Compiled from "Math.java"
public class com.wkp.jvm.Math {
  public static final java.lang.Integer CONSTANT;
 
  static {};
    Code:
       0: sipush        666
       3: invokestatic  #10                 // Method java/lang/Integer.valueOf:(I)Ljava/lang/Integer;
       6: putstatic     #16                 // Field CONSTANT:Ljava/lang/Integer;
       9: return
 
  public com.wkp.jvm.Math();
    Code:
       0: aload_0
       1: invokespecial #21                 // Method java/lang/Object."<init>":()V
       4: return
 
  public int compute();
    Code:
       0: iconst_3			//將int類型的3推送至棧頂
       1: istore_1			//將棧頂int類型數(shù)值（上面的3）出棧并存入第二個本地變量
       2: iconst_5			//將int類型的5推送至棧頂
       3: istore_2			//將棧頂int類型數(shù)值（上面的5）出棧并存入第三個本地變量
       4: iload_1			//將第二個int型本地變量（上面的3）推送至棧頂
       5: iload_2			//將第三個int型本地變量（上面的5）推送至棧頂
       6: iadd				//將棧頂兩int型數(shù)值出棧，然后相加并將結(jié)果壓入棧頂
       7: bipush        10	        //將常量值10推送至棧頂
       9: imul				//將棧頂兩int型數(shù)值出棧，然后相乘并將結(jié)果壓入棧頂
      10: istore_3			//將棧頂int類型數(shù)值（上面的乘積）出棧并存入第四個本地變量
      11: iload_3			//將第四個int類型本地變量推送至棧頂
      12: ireturn			//從當前方法返回int類型值
 
  public static void main(java.lang.String[]);
    Code:
       0: new           #1                  // class com/wkp/jvm/Math
       3: dup
       4: invokespecial #33                 // Method "<init>":()V
       7: astore_1
       8: aload_1
       9: invokevirtual #34                 // Method compute:()I
      12: pop
      13: return
}

public int compute();
    LineNumberTable:
      line 8: 0
      line 9: 2
      line 10: 4
      line 11: 11
    LocalVariableTable:
      Start  Length  Slot  Name   Signature
          0      13     0  this   Lcom/wkp/jvm/Math;
          2      11     1     a   I
          4       9     2     b   I
         11       2     3     c   I

Classfile /D:/wyonline/myworkspaces/framework/Test/bin/com/wkp/jvm/Math.class
  Last modified 2019-8-24; size 761 bytes
  MD5 checksum be0cdf4bcd037929d3fe0af86d44a837
  Compiled from "Math.java"
public class com.wkp.jvm.Math
  minor version: 0
  major version: 52		//魔數(shù)
  flags: ACC_PUBLIC, ACC_SUPER
Constant pool:		//常量池
   #1 = Class              #2             // com/wkp/jvm/Math
   #2 = Utf8               com/wkp/jvm/Math
   #3 = Class              #4             // java/lang/Object
   #4 = Utf8               java/lang/Object
   #5 = Utf8               CONSTANT
   #6 = Utf8               Ljava/lang/Integer;
   #7 = Utf8               <clinit>
   #8 = Utf8               ()V
   #9 = Utf8               Code
  #10 = Methodref          #11.#13        // java/lang/Integer.valueOf:(I)Ljava/lang/Integer;
  #11 = Class              #12            // java/lang/Integer
  #12 = Utf8               java/lang/Integer
  #13 = NameAndType        #14:#15        // valueOf:(I)Ljava/lang/Integer;
  #14 = Utf8               valueOf
  #15 = Utf8               (I)Ljava/lang/Integer;
  #16 = Fieldref           #1.#17         // com/wkp/jvm/Math.CONSTANT:Ljava/lang/Integer;
  #17 = NameAndType        #5:#6          // CONSTANT:Ljava/lang/Integer;
  #18 = Utf8               LineNumberTable
  #19 = Utf8               LocalVariableTable
  #20 = Utf8               <init>
  #21 = Methodref          #3.#22         // java/lang/Object."<init>":()V
  #22 = NameAndType        #20:#8         // "<init>":()V
  #23 = Utf8               this
  #24 = Utf8               Lcom/wkp/jvm/Math;
  #25 = Utf8               compute
  #26 = Utf8               ()I
  #27 = Utf8               a
  #28 = Utf8               I
  #29 = Utf8               b
  #30 = Utf8               c
  #31 = Utf8               main
  #32 = Utf8               ([Ljava/lang/String;)V
  #33 = Methodref          #1.#22         // com/wkp/jvm/Math."<init>":()V
  #34 = Methodref          #1.#35         // com/wkp/jvm/Math.compute:()I
  #35 = NameAndType        #25:#26        // compute:()I
  #36 = Utf8               args
  #37 = Utf8               [Ljava/lang/String;
  #38 = Utf8               math
  #39 = Utf8               SourceFile
  #40 = Utf8               Math.java
{
  public static final java.lang.Integer CONSTANT;
    descriptor: Ljava/lang/Integer;
    flags: ACC_PUBLIC, ACC_STATIC, ACC_FINAL
 
  static {};
    descriptor: ()V
    flags: ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: sipush        666
         3: invokestatic  #10                 // Method java/lang/Integer.valueOf:(I)Ljava/lang/Integer;
         6: putstatic     #16                 // Field CONSTANT:Ljava/lang/Integer;
         9: return
      LineNumberTable:
        line 5: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
 
  public com.wkp.jvm.Math();
    descriptor: ()V
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial #21                 // Method java/lang/Object."<init>":()V
         4: return
      LineNumberTable:
        line 3: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       5     0  this   Lcom/wkp/jvm/Math;
 
  public int compute();
    descriptor: ()I
    flags: ACC_PUBLIC
    Code:
      stack=2, locals=4, args_size=1
         0: iconst_3
         1: istore_1
         2: iconst_5
         3: istore_2
         4: iload_1
         5: iload_2
         6: iadd
         7: bipush        10
         9: imul
        10: istore_3
        11: iload_3
        12: ireturn
      LineNumberTable:
        line 8: 0
        line 9: 2
        line 10: 4
        line 11: 11
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0      13     0  this   Lcom/wkp/jvm/Math;
            2      11     1     a   I
            4       9     2     b   I
           11       2     3     c   I
 
  public static void main(java.lang.String[]);
    descriptor: ([Ljava/lang/String;)V
    flags: ACC_PUBLIC, ACC_STATIC
    Code:
      stack=2, locals=2, args_size=1
         0: new           #1                  // class com/wkp/jvm/Math
         3: dup
         4: invokespecial #33                 // Method "<init>":()V
         7: astore_1
         8: aload_1
         9: invokevirtual #34                 // Method compute:()I
        12: pop
        13: return
      LineNumberTable:
        line 15: 0
        line 16: 8
        line 17: 13
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0      14     0  args   [Ljava/lang/String;
            8       6     1  math   Lcom/wkp/jvm/Math;
}
SourceFile: "Math.java"