Java 嵌套回调太深

如何替换嵌套回调（Testing.java）以便于阅读：

if(isValidGenderID() && isValidReligionID() && isValidMaritalID()){
   // DO PRIMARY TASK
}

嵌套回调太深，使程序不易阅读！。如何解决这个问题

//PersonValidation.java

public static void isValidGenderID(@NonNull Context context, int genderID, final IGenderDataSource.IIsExistGenderIDCallback callback) {

    GenderDataSource.getInstance(context).isExistGenderID(genderID, new IGenderDataSource.IIsExistGenderIDCallback() {
        @Override
        public void onSuccess(boolean result) {
            callback.onSuccess(result);
        }

        @Override
        public void onFailure(String result) {
            callback.onFailure(result);
        }
    });
}

public static void isValidReligionID(@NonNull Context context, int religionID, final IReligionDataSource.IIsExistReligionIDCallback callback) {
        ReligionDataSource.getInstance(context).isExistReligionID(religionID, new IReligionDataSource.IIsExistReligionIDCallback() {
        @Override
        public void onSuccess(boolean result) {
            callback.onSuccess(result);
        }

        @Override
        public void onFailure(String result) {
            callback.onFailure(result);
        }
    });
}

public static void isValidMaritalID(@NonNull Context context, int maritalID, final IMaritalDataSource.IIsExistMaritalIDCallback callback) {
        MaritalDataSource.getInstance(context).isExistMaritalID(maritalID, new IMaritalDataSource.IIsExistMaritalIDCallback() {
        @Override
        public void onSuccess(boolean result) {
            callback.onSuccess(result);
        }

        @Override
        public void onFailure(String result) {
            callback.onFailure(result);
        }
    });
}

//GenderDataSource.java

@Override
public void isExistGenderID(final int ID, @NonNull final IIsExistGenderIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistReligionID(final int ID, @NonNull final IIsExistReligionIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistMaritalID(final int ID, @NonNull final IIsExistMaritalIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();

        }
    };
    appExecutors.getLocalDb().execute(r);
}

//religinandasource.java

@Override
public void isExistGenderID(final int ID, @NonNull final IIsExistGenderIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistReligionID(final int ID, @NonNull final IIsExistReligionIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistMaritalID(final int ID, @NonNull final IIsExistMaritalIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();

        }
    };
    appExecutors.getLocalDb().execute(r);
}

//MaritalDataSource.java

@Override
public void isExistGenderID(final int ID, @NonNull final IIsExistGenderIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistReligionID(final int ID, @NonNull final IIsExistReligionIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();
        }
    };
    appExecutors.getLocalDb().execute(r);
}

@Override
public void isExistMaritalID(final int ID, @NonNull final IIsExistMaritalIDCallback callback) {
    Runnable r = new Runnable() {
        @Override
        public void run() {
            db.sqlRawQuery();
            callback.onSuccess();

        }
    };
    appExecutors.getLocalDb().execute(r);
}

//java（嵌套调用太深，使程序不易阅读）