HowTo use ByteBuddy to measure time taken by annotaion marked methods intrumented via agent - byte-buddy

Question

I'm using ByteBuddy to make some perfomance measuremnts of certian methods. Therefore, I'm annotating the interessting ones. As the method signature is not stable, I choose the generic way for my interceptor:
public class ChronometryInterception {
#RuntimeType
public Object intercept(#Origin MethodHandle methodHandle, #AllArguments Object[] allArguments, #Origin Method method) throws Exception {
System.out.println("in interceptor");
long startTime = System.currentTimeMillis();
try {
return methodHandle.invoke(allArguments);
} catch (Throwable e) {
System.out.println("ex in interceptor " + e.getMessage());
throw new Exception(e);
} finally {
long elapsedTime = System.currentTimeMillis() - startTime;
System.out.println("took " + elapsedTime;
}
}
}
and I bind it in my premain() like this
ChronometryInterception chronometryInterception = new ChronometryInterception();
new AgentBuilder.Default()
.with(AgentBuilder.Listener.StreamWriting.toSystemOut())
.type(declaresMethod(isAnnotatedWith(Timed.class)))
.transform((builder, type, classLoader, module) -> builder
.method(isAnnotatedWith(Timed.class))
.intercept(MethodDelegation.to(chronometryInterception))
).installOn(instrumentation);
In the listener stream, I can see the annotated classes have been transformed and they try to do something, but in end up with a NPE. Using the debugger, I'm not getting anywhere in the ChronometryInterception. Any way out? Thanks!

Answer 1

I have found a working solution. At the end, the method signature of my interceptor was not ok. This one is working, even with an instance of the ChronometryInterception:
public class ChronometryInterception {
#RuntimeType
public Object intercept(#SuperCall Callable<?> zuper) throws Exception {
long startTime = System.currentTimeMillis();
try {
return zuper.call();
} catch (Exception e) {
throw e;
} finally {
long elapsedTime = System.currentTimeMillis() - startTime;
System.out.println("took " + elapsedTime);
}
}
}