Clear exceptions before calling IsInstanceOf.

    if (env->ExceptionCheck()) {

        jthrowable excep = env->ExceptionOccurred();

        env->ExceptionDescribe();

        env->ExceptionClear();

        // It is illegal to call IsInstanceOf if there is a pending exception.

        // Attempting to do so results in a JniAbort which crashes the entire process.

        if (env->IsInstanceOf(excep, gErrorClass)) {

            /* It's an error */

            LOG(ERROR) << "Forcefully exiting";

            exit(1);

        } else {

            env->ExceptionClear();

            LOG(ERROR) << "Uncaught exception!";

        }