public class Test {
public void foo(){
bar();
}
public void bar(){
}
}
Classfile /Users/yangdiansheng/Desktop/javacode/JavaTest/out/production/JavaTest/Test.class
Last modified 2019-7-2; size 381 bytes
MD5 checksum 8df2469155792718b33ba9c334da87c3
Compiled from "Test.java"
public class Test
minor version: 0
major version: 52
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #4.#16 // java/lang/Object."<init>":()V
#2 = Methodref #3.#17 // Test.bar:()V
#3 = Class #18 // Test
#4 = Class #19 // java/lang/Object
#5 = Utf8 <init>
#6 = Utf8 ()V
#7 = Utf8 Code
#8 = Utf8 LineNumberTable
#9 = Utf8 LocalVariableTable
#10 = Utf8 this
#11 = Utf8 LTest;
#12 = Utf8 foo
#13 = Utf8 bar
#14 = Utf8 SourceFile
#15 = Utf8 Test.java
#16 = NameAndType #5:#6 // "<init>":()V
#17 = NameAndType #13:#6 // bar:()V
#18 = Utf8 Test
#19 = Utf8 java/lang/Object
{
public Test();
descriptor: ()V
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 1: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this LTest;
public void foo();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokevirtual #2 // Method bar:()V
4: return
LineNumberTable:
line 4: 0
line 5: 4
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this LTest;
public void bar();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=0, locals=1, args_size=1
0: return
LineNumberTable:
line 9: 0
LocalVariableTable:
Start Length Slot Name Signature
0 1 0 this LTest;
}
SourceFile: "Test.java"
方法表
https://blog.csdn.net/luanlouis/article/details/41113695
直接引用和符号引用
https://blog.csdn.net/u014656992/article/details/51107127
public class Test implements Father{
private int aa = 0;
protected float bb = 1;
public Test test = new Test();
public static void main(String[] args){
Test test = new Test();
try {
int sum = test.sum(1,2);
if (sum == 3){
test.foo();
}
} catch (Exception e){
}
}
public void foo(){
System.out.println("sum = " + 3);
}
public int sum(int i,int j){
return i + j;
}
@Override
public void show() {
foo();
}
}
Classfile /Users/yangdiansheng/Desktop/javacode/JavaTest/out/production/JavaTest/Test.class
Last modified 2019-7-3; size 1045 bytes
MD5 checksum 043f5cd328f8fa88b0e8f594b399495e
Compiled from "Test.java"
public class Test implements Father
minor version: 0
major version: 52
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #13.#42 // java/lang/Object."<init>":()V
#2 = Fieldref #4.#43 // Test.aa:I
#3 = Fieldref #4.#44 // Test.bb:F
#4 = Class #45 // Test
#5 = Methodref #4.#42 // Test."<init>":()V
#6 = Fieldref #4.#46 // Test.test:LTest;
#7 = Methodref #4.#47 // Test.sum:(II)I
#8 = Methodref #4.#48 // Test.foo:()V
#9 = Class #49 // java/lang/Exception
#10 = Fieldref #50.#51 // java/lang/System.out:Ljava/io/PrintStream;
#11 = String #52 // sum = 3
#12 = Methodref #53.#54 // java/io/PrintStream.println:(Ljava/lang/String;)V
#13 = Class #55 // java/lang/Object
#14 = Class #56 // Father
#15 = Utf8 aa
#16 = Utf8 I
#17 = Utf8 bb
#18 = Utf8 F
#19 = Utf8 test
#20 = Utf8 LTest;
#21 = Utf8 <init>
#22 = Utf8 ()V
#23 = Utf8 Code
#24 = Utf8 LineNumberTable
#25 = Utf8 LocalVariableTable
#26 = Utf8 this
#27 = Utf8 main
#28 = Utf8 ([Ljava/lang/String;)V
#29 = Utf8 sum
#30 = Utf8 args
#31 = Utf8 [Ljava/lang/String;
#32 = Utf8 StackMapTable
#33 = Class #45 // Test
#34 = Class #49 // java/lang/Exception
#35 = Utf8 foo
#36 = Utf8 (II)I
#37 = Utf8 i
#38 = Utf8 j
#39 = Utf8 show
#40 = Utf8 SourceFile
#41 = Utf8 Test.java
#42 = NameAndType #21:#22 // "<init>":()V
#43 = NameAndType #15:#16 // aa:I
#44 = NameAndType #17:#18 // bb:F
#45 = Utf8 Test
#46 = NameAndType #19:#20 // test:LTest;
#47 = NameAndType #29:#36 // sum:(II)I
#48 = NameAndType #35:#22 // foo:()V
#49 = Utf8 java/lang/Exception
#50 = Class #57 // java/lang/System
#51 = NameAndType #58:#59 // out:Ljava/io/PrintStream;
#52 = Utf8 sum = 3
#53 = Class #60 // java/io/PrintStream
#54 = NameAndType #61:#62 // println:(Ljava/lang/String;)V
#55 = Utf8 java/lang/Object
#56 = Utf8 Father
#57 = Utf8 java/lang/System
#58 = Utf8 out
#59 = Utf8 Ljava/io/PrintStream;
#60 = Utf8 java/io/PrintStream
#61 = Utf8 println
#62 = Utf8 (Ljava/lang/String;)V
{
private int aa;
descriptor: I
flags: ACC_PRIVATE
protected float bb;
descriptor: F
flags: ACC_PROTECTED
public Test test;
descriptor: LTest;
flags: ACC_PUBLIC
//无参构造函数
public Test();
//方法描述符
descriptor: ()V
//访问权限
flags: ACC_PUBLIC
//执行指令存储在code中
Code:
//stack操作数栈最大深度，locals局部变量表中变量数，args_size参数
stack=3, locals=1, args_size=1
//将局部变量表第0位置入操作数栈 ，super父类构造函数
0: aload_0 .
//调用父类构造方法
1: invokespecial #1 // Method java/lang/Object."<init>":()V
//this引用入栈
4: aload_0
//int类型常量入栈
5: iconst_0
//成员变量赋值
6: putfield #2 // Field aa:I
//this引用入栈
9: aload_0
//float类型常量入栈
10: fconst_1
//成员变量赋值
11: putfield #3 // Field bb:F
//this引用入栈
14: aload_0
//创建实例
15: new #4 // class Test
//复制栈顶
18: dup
//执行<init>方法，也就是对象初始化方法
19: invokespecial #5 // Method "<init>":()V
//成员变量赋值
22: putfield #6 // Field test:LTest;
//返回
25: return
LineNumberTable:
line 3: 0
line 5: 4
line 6: 9
line 7: 14
LocalVariableTable:
Start Length Slot Name Signature
0 26 0 this LTest;
public static void main(java.lang.String[]);
descriptor: ([Ljava/lang/String;)V
flags: ACC_PUBLIC, ACC_STATIC
Code:
stack=3, locals=3, args_size=1
//创建实例
0: new #4 // class Test
//复制栈顶
3: dup
//调用<init方法>
4: invokespecial #5 // Method "<init>":()V
//存储数值到局部变量表位置1，此时test局部变量赋值完毕
7: astore_1
//局部变量表1位置转载到栈
8: aload_1
//int类型常量入栈
9: iconst_1
//int类型常量入栈
10: iconst_2
//调用sum方法
11: invokevirtual #7 // Method sum:(II)I
//存储数值到局部变量表位置2，此时sum赋值完毕
14: istore_2
//int类型常量入栈，sum中值入栈
15: iload_2
// int类型常量入栈
16: iconst_3
// 比较指令
17: if_icmpne 24
//取对象test
20: aload_1
// 调用foo()方法
21: invokevirtual #8 // Method foo:()V
// 跳转指令
24: goto 28
//
27: astore_2
28: return
Exception table:
from to target type
8 24 27 Class java/lang/Exception
LineNumberTable:
line 10: 0
line 12: 8
line 13: 15
line 14: 20
line 18: 24
line 16: 27
line 19: 28
LocalVariableTable:
Start Length Slot Name Signature
15 9 2 sum I
0 29 0 args [Ljava/lang/String;
8 21 1 test LTest;
StackMapTable: number_of_entries = 3
frame_type = 252 /* append */
offset_delta = 24
locals = [ class Test ]
frame_type = 66 /* same_locals_1_stack_item */
stack = [ class java/lang/Exception ]
frame_type = 0 /* same */
public void foo();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=2, locals=1, args_size=1
//访问static字段
0: getstatic #10 // Field java/lang/System.out:Ljava/io/PrintStream;
//常量压入栈
3: ldc #11 // String sum = 3
//调用println方法
5: invokevirtual #12 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
8: return
LineNumberTable:
line 22: 0
line 23: 8
LocalVariableTable:
Start Length Slot Name Signature
0 9 0 this LTest;
public int sum(int, int);
descriptor: (II)I
flags: ACC_PUBLIC
Code:
stack=2, locals=3, args_size=3
0: iload_1
1: iload_2
2: iadd
3: ireturn
LineNumberTable:
line 26: 0
LocalVariableTable:
Start Length Slot Name Signature
0 4 0 this LTest;
0 4 1 i I
0 4 2 j I
public void show();
descriptor: ()V
flags: ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokevirtual #8 // Method foo:()V
4: return
LineNumberTable:
line 31: 0
line 32: 4
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this LTest;
}
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