public int openAccessory() throws Exception { /* Open stuff */ }
public int closeAccessory() throws IOException { /* Close stuff */ }

int AOAConnection::Open () {
    JNIEnvironmentAttacher jea(&this->JNIE);
    return JavaObject.callMethod<jint>("openAccessory");
}

int AOAConnection::Close () {
    JNIEnvironmentAttacher jea(&this->JNIE);
    return JavaObject.callMethod<jint>("closeAccessory", "(V)I");
}

return JavaObject.callMethod<jint>("openAccessory", "(V)I");