源代码为：
package com.test19;
public class Test04 {
void spin(){
int i;
for(i=0;i<100;i++){
;
}
i = 0;
}
}
生成的class如下：
public class com.test19.Test04
SourceFile: "Test04.java"
minor version: 0
major version: 51
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #3.#17 // java/lang/Object."<init>":()V
#2 = Class #18 // com/test19/Test04
#3 = Class #19 // java/lang/Object
#4 = Utf8 <init>
#5 = Utf8 ()V
#6 = Utf8 Code
#7 = Utf8 LineNumberTable
#8 = Utf8 LocalVariableTable
#9 = Utf8 this
#10 = Utf8 Lcom/test19/Test04;
#11 = Utf8 spin
#12 = Utf8 i
#13 = Utf8 I
#14 = Utf8 StackMapTable
#15 = Utf8 SourceFile
#16 = Utf8 Test04.java
#17 = NameAndType #4:#5 // "<init>":()V
#18 = Utf8 com/test19/Test04
#19 = Utf8 java/lang/Object
{
public com.test19.Test04();
flags: ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
LineNumberTable:
line 2: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/test19/Test04;
void spin();
flags:
Code:
stack=2, locals=2, args_size=1
0: iconst_0
1: istore_1
2: iload_1
3: bipush 100
5: if_icmpge 14
8: iinc 1, 1
11: goto 2
14: iconst_0
15: istore_1
16: return
LineNumberTable:
line 5: 0
line 9: 14
line 10: 16
LocalVariableTable:
Start Length Slot Name Signature
0 17 0 this Lcom/test19/Test04;
2 15 1 i I
StackMapTable: number_of_entries = 2
frame_type = 252 /* append */
offset_delta = 2
locals = [ int ]
frame_type = 11 /* same */
}
Code编码为：
03 3C 1B 10 64 A2 00 09 84 01 01 A7 FF F7 03 3C B1
opcode [03] - 0000: iconst_0
opcode [3C] - 0001: istore_1
opcode [1B] - 0002: iload_1
opcode [10] - 0003: bipush 100
opcode [A2] - 0005: if_icmpge 9
opcode [84] - 0008: iinc 1 1 ; index const
opcode [A7] - 0011: goto -9
opcode [03] - 0014: iconst_0
opcode [3C] - 0015: istore_1
opcode [B1] - 0016: return
3 60 27 16 100
-94 0 9 -124 1
1 -89 -1 -9 -79