tblair / native-intercept Goto Github PK

Hello,

Can anyone please put a guide how to use the native-intercept ?

Thanks

What steps will reproduce the problem?
1. Create class with "native void someMethod(int x)".
2. Intercept native calls for the class from #1.
3. Invoke someMethod().


What is the expected output? What do you see instead?
Expected to have InvocationHandler invoked for the method. I got an
exception instead:

Exception in thread "main" java.lang.IllegalStateException: Unexpected
exception thrown in interceptor
    at com.google.nativeproxy.ContainsNative.nativeMethod_V_I(ContainsNative.java)
    at com.google.nativeproxy.NpDemo.run(NpDemo.java:27)
    at com.google.nativeproxy.NpDemo.main(NpDemo.java:34)
Caused by: java.lang.NoClassDefFoundError: I
    ... 3 more
Caused by: java.lang.ClassNotFoundException: I
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:336)
    ... 3 more

What version of the product are you using? On what operating system?
0.1.1-pre-alpha

Please provide any additional information below.

What steps will reproduce the problem?
1. Subclass a class declaring a native.
2. Invoke the native through the subclass.
3.

What is the expected output? What do you see instead?
Expected to have InvocationHandler invoked for native method. Got an
exception instead:

java.lang.IllegalStateException: Attempt to intercept non-existent native
method
    at org.synth.intercept.NativeInvocationHandler.findMethod(Unknown Source)
    at org.synth.intercept.NativeInvocationHandler.handleObject(Unknown Source)
...

What version of the product are you using? On what operating system?
0.1.1 prealpha

Please provide any additional information below.
It looks like NativeInvocationHandler.findMethod should keep looking at
parent classes if it can't find a declared method.

Hello,

this is my test program:

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import org.synth.intercept.NativeInterceptor;
public class Test {
    public static void main(String[] args) throws ClassNotFoundException {
        NativeInterceptor.intercept(Class.forName("java.net.PlainSocketImpl"),
                new MyInvocationHandler());
    }
    static class MyInvocationHandler implements InvocationHandler {
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            System.out.println("Proxy: " + proxy + "\nMethod: " + method + "\n");
            return null;
        }
    }
}

and this is how I'm invoking it (CLASSPATH is set, tools.jar is added too):

java -javaagent:../lib/native-interceptor-0.1.3-alpha.jar Test

However I get following exception:

Exception in thread "main" java.lang.IllegalStateException: Cannot instrument 
class to intercept native methods...see documentation for causes
    at org.synth.intercept.NativeInterceptor.intercept(NativeInterceptor.java:58)
    at org.synth.intercept.NativeInterceptor.intercept(NativeInterceptor.java:29)
    at Test.main(Test.java:13)

I checked the code (from SVN, not sure if it's same as in 0.1.3-alpha) and this 
exception is thrown if following check fails:

if (type.getAnnotation(HasNatives.class) == null)
    throw new ...

Is it neccessary to use @HasNative annotation?

Thank you.