public void t(String d){
final String str = "b";
String s = "a"+"c"+str+d;
}
class文件反编译后内容如下：
public void t(String d) {
String str = "b";
(new StringBuilder()).append("acb").append(d).toString();
}
则被编译的class文件如下：
public class com.test19.Test07
SourceFile: "Test07.java"
Utf8 1533966651178Utf8 1533966851637minor version: 0
major version: 51
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #9.#30 // java/lang/Object."<init>":()V
#2 = String #31 // b
#3 = Class #32 // java/lang/StringBuilder
#4 = Methodref #3.#30 // java/lang/StringBuilder."<init>":()V
#5 = String #33 // acb
#6 = Methodref #3.#34 // java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
#7 = Methodref #3.#35 // java/lang/StringBuilder.toString:()Ljava/lang/String;
#8 = Class #36 // com/test19/Test07
#9 = Class #37 // java/lang/Object
#10 = Utf8 <init>
#11 = Utf8 ()V
#12 = Utf8 Code
#13 = Utf8 LineNumberTable
#14 = Utf8 CharacterRangeTable
#15 = Utf8 LocalVariableTable
#16 = Utf8 this
#17 = Utf8 Lcom/test19/Test07;
#18 = Utf8 t
#19 = Utf8 (Ljava/lang/String;)V
#20 = Utf8 d
#21 = Utf8 Ljava/lang/String;
#22 = Utf8 str
#23 = Utf8 s
#24 = Utf8 SourceFile
#25 = Utf8 Test07.java
#26 = Utf8 SourceID
#27 = Utf8 1533966651178
#28 = Utf8 CompilationID
#29 = Utf8 1533966851637
#30 = NameAndType #10:#11 // "<init>":()V
#31 = Utf8 b
#32 = Utf8 java/lang/StringBuilder
#33 = Utf8 acb
#34 = NameAndType #38:#39 // append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
#35 = NameAndType #40:#41 // toString:()Ljava/lang/String;
#36 = Utf8 com/test19/Test07
#37 = Utf8 java/lang/Object
#38 = Utf8 append
#39 = Utf8 (Ljava/lang/String;)Ljava/lang/StringBuilder;
#40 = Utf8 toString
#41 = Utf8 ()Ljava/lang/String;
{
public com.test19.Test07();
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 34: 0
CharacterRangeTable:
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/test19/Test07;
public void t(java.lang.String);
flags: ACC_PUBLIC
Code:
stack=2, locals=4, args_size=2
0: ldc #2 // String b
2: astore_2
3: new #3 // class java/lang/StringBuilder
6: dup
7: invokespecial #4 // Method java/lang/StringBuilder."<init>":()V
10: ldc #5 // String acb
12: invokevirtual #6 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
15: aload_1
16: invokevirtual #6 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
19: invokevirtual #7 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
22: astore_3
23: return
LineNumberTable:
line 63: 0
line 64: 3
line 65: 23
CharacterRangeTable:
0, 2, fc10, fc1a, 1 // 0, 2, 63:16, 63:26, sta tement
3, 22, 1000a, 1001c, 1 // 3, 22, 64:10, 64:28, sta tement
0, 23, f819, 10402, 2 // 0, 23, 62:25, 65:02, blo ck
LocalVariableTable:
Start Length Slot Name Signature
0 24 0 this Lcom/test19/Test07;
0 24 1 d Ljava/lang/String;
3 21 2 str Ljava/lang/String;
23 1 3 s Ljava/lang/String;
}