get Permission for android app,

activity.java

import java.util.List;
import android.content.pm.PackageManager;
import androidx.core.app.ActivityCompat;
import java.util.ArrayList;

// get all permission
private void checkPermissions() {
        String[] permissions = new String[]{
                Manifest.permission.READ_EXTERNAL_STORAGE,
                Manifest.permission.ACCESS_NOTIFICATION_POLICY,
                Manifest.permission.CAMERA,
        };
        int result;
        List<String> listPermissionsNeeded = new ArrayList<>();
        for (String p : permissions) {
            result = ContextCompat.checkSelfPermission(this, p);
            if (result != PackageManager.PERMISSION_GRANTED) {
                listPermissionsNeeded.add(p);
            }
        }
        if (!listPermissionsNeeded.isEmpty()) {
            ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]), 100);
        }
}