btrace和java.lang.NoSuchMethodError的奇怪之处

Question

主修班：

package com.xxx.yyy;

public class Hello{
    public static void main(String[] args){
        A a = new A();
        while(true){
            try {
                a.execute(1000);
                Thread.sleep(1000);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

A类：

package com.xxx.yyy;

public class A{
    public void execute(int sleepTime) throws Exception {
        System.out.println("sleep time is "+sleepTime); 
    }
}

btrace脚本：

import static com.sun.btrace.BTraceUtils.println;  
import static com.sun.btrace.BTraceUtils.str;  
import static com.sun.btrace.BTraceUtils.strcat;  
import static com.sun.btrace.BTraceUtils.timeMillis;  

import com.sun.btrace.annotations.BTrace;  
import com.sun.btrace.annotations.Kind;  
import com.sun.btrace.annotations.Location;  
import com.sun.btrace.annotations.OnMethod;  
import com.sun.btrace.annotations.ProbeClassName;  
import com.sun.btrace.annotations.ProbeMethodName;  
import com.sun.btrace.annotations.TLS;
@BTrace
public class BtraceTest{

    @OnMethod(clazz="com.xxx.yyy.A",method="execute",location=@Location(Kind.RETURN))
    public static void traceExecute(@ProbeClassName String name,@ProbeMethodName String method,int sleepTime){
        println(strcat("the class name=>", name));  
        println(strcat("the class method=>", method));  
        println(strcat("the class method params=>", str(sleepTime)));
    }
}

一切都很好。但是:当我将行Thread.sleep(1000)移到A类的execute函数时，如下所示：

package com.xxx.yyy;

public class A{
    public void execute(int sleepTime) throws Exception {
        System.out.println("sleep time is "+sleepTime); 
        Thread.sleep(1000);
    }
}

NoSuchMethodError是由Hello抛出的。

Exception in thread "main" java.lang.NoSuchMethodError: com.xxx.yyy.A.$btrace$BtraceTest$traceExecute(Ljava/lang/String;Ljava/lang/String;I)V
    at com.xxx.yyy.A.execute(Unknown Source)
    at com.xxx.yyy.Hello.main(Hello.java:8)

我的环境是

java版本"1.8.0_121“ BTrace诉1.3.9 (20170111)

谁能解释原因?谢谢！

Answer 1

我认为你的课应该是implements Runnable或extends Thread。然后，只有您可以在您的程序中使用start、sleep和类似的方法。看看这里，了解如何实现线程方法。