在Kotlin中,有同步块
synchronized(_lock) {
// code do something
}
这意味着释放锁定,直到完成所有// code fo something
。
但是在反编译的Java代码中,synchronized(lock)块放在了代码块之外
Object var1 = this._lock;
synchronized(var1){}
// code do something
,这是否意味着该锁将在// code fo something
仍在运行的情况下释放得太早?
kotlin代码:
override fun doSomething(): Boolean {
synchronized(_lock) {
//......
lastCompleteAt = Date().time + REQUEST_THROTTLE_TIME
for ((_, handler) in dataRequestMap) {
//......
}
return true
}
}
反编译为Java代码:
public boolean doSomething() {
Object var1 = this._lock;
synchronized(var1){}
boolean var7;
try {
//......
this.lastCompleteAt = (new Date()).getTime() + 5000L;
Map var3 = (Map)this.dataRequestMap;
Iterator var4 = var3.entrySet().iterator();
while(var4.hasNext()) {
//......
}
//......
var7 = true;
} finally {
;
}
return var7;
}
答案 0 :(得分:2)
我相信@tkausl is correct的原因在于,您的反编译器只是错误地反编译了代码。如果您检查由以下内容生成的字节码:
fun main() {
val lock = Any()
synchronized(lock) {
println("Hello, World!")
}
}
您会看到:
Compiled from "Main.kt"
public final class MainKt {
public static final void main();
Code:
0: new #4 // class java/lang/Object
3: dup
4: invokespecial #12 // Method java/lang/Object."<init>":()V
7: astore_0
8: iconst_0
9: istore_1
10: iconst_0
11: istore_2
12: aload_0
13: monitorenter
14: nop
15: iconst_0
16: istore_3
17: ldc #14 // String Hello, World!
19: astore 4
21: iconst_0
22: istore 5
24: getstatic #20 // Field java/lang/System.out:Ljava/io/PrintStream;
27: aload 4
29: invokevirtual #26 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
32: getstatic #32 // Field kotlin/Unit.INSTANCE:Lkotlin/Unit;
35: astore_2
36: aload_0
37: monitorexit
38: goto 46
41: astore_2
42: aload_0
43: monitorexit
44: aload_2
45: athrow
46: return
Exception table:
from to target type
14 36 41 any
41 42 41 any
public static void main(java.lang.String[]);
Code:
0: invokestatic #9 // Method main:()V
3: return
}
如果您注意到,在13
语句(println("Hello, World")
)之前有一个“ monitorenter”命令(29
),然后是“ monitorexit”命令(37
)。