I am currently working on creating some Java bindings for a C library I work on. One of our C-structs has a char buffer that is a file system path. After calling the C function, the buffer is correctly populated. I want to take the buffer and convert it to a java.nio.file.Path member on the Java object.
I am having some trouble however. I for some reason am generating a NullPointerException within C, and I can't really see the problem.
The way to create a java.nio.file.Path object is going through java.nio.file.Paths::get().
Here is the relevant C code:
const jclass paths_class = (*env)->FindClass(env, "java/nio/file/Paths");
if ((*env)->ExceptionCheck(env))
return;
const jmethodID get_method = (*env)->GetStaticMethodID(
env, paths_class, "get", "(Ljava/lang/String;[Ljava/lang/String;)Ljava/nio/file/Path;");
if ((*env)->ExceptionCheck(env))
return;
const jstring path_str = (*env)->NewStringUTF(env, info.mi_path);
if ((*env)->ExceptionCheck(env))
return;
const jobject path_obj =
(*env)->CallStaticObjectMethod(env, paths_class, get_method, path_str); // exception generated here
if ((*env)->ExceptionCheck(env))
return;
And the Java class for good measure:
public final class MclassInfo {
private native void _get(final Kvdb kvdb, Mclass mclass) throws HseException;
private long allocatedBytes;
private long usedBytes;
private Path path;
MclassInfo(final Kvdb kvdb, final Mclass mclass) throws HseException {
_get(kvdb, mclass);
}
public long getAllocatedBytes() {
return allocatedBytes;
}
public long getUsedBytes() {
return usedBytes;
}
public Path getPath() {
return path;
}
}
All I can think is that somehow I am not calling the Java variadic function properly. I have also tried passing NULL as an extra argument to the method call, but ended up with the same issue.