[Demonstration 1]

[Buggy Method]
private Observable<String> createFingerPrintObservable() {
    return Observable.create((ObservableEmitter<String> emitter) -> {
        if (isFingerPrintExist() && isNoErrorDetected()) {
            if (isPermissionGranted()) {
                emitter.onNext(null);
            } else {
                requestPermission();
            }
        } else {
            emitter.onError(new Throwable());
        }
    });
}

[Buggy Hunk]
emitter.onNext(null);

[Patch]
emitter.onNext("");

[Demonstration 2]

[Buggy Method]
public short checkToLose() {
    return this.rule.toLose(ChessStatus);
}

[Buggy Hunk]
return this.rule.toLose(ChessStatus);

[Patch]
return this.rule.lose(ChessStatus);