Download Android Development Certificate Practice Exam: Java and XML and more Exams Technology in PDF only on Docsity!
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Certificate Practice Exam
Question 1. Which keyword in Java is used to restrict a class so that it cannot be subclassed? A) final B) static C) abstract D) protected Answer: A Explanation: Declaring a class as final prevents other classes from extending it. Question 2. In Java, which access modifier makes a member visible only within its own package and to subclasses in other packages? A) private B) protected C) public D) default Answer: B Explanation: protected members are accessible within the same package and by subclasses even if they are in different packages. Question 3. Which of the following collections maintains insertion order and allows duplicate elements? A) HashSet B) TreeSet C) ArrayList D) LinkedHashMap
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Answer: C Explanation: ArrayList preserves the order of insertion and permits duplicates. Question 4. What is the output of the following code? String s = "Hello"; s.concat(" World"); System.out.println(s); A) Hello World B) Hello C) null D) Compilation error Answer: B Explanation: String.concat returns a new string; the original s remains unchanged. Question 5. Which interface must a class implement to be used as a target for a lambda expression that takes no arguments and returns no value? A) Callable B) Runnable C) Comparable D) Serializable Answer: B Explanation: Runnable’s run() method matches a lambda with no parameters and no return value. Question 6. In Java exception handling, which block is always executed regardless of whether an exception occurs? A) try
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Question 9. In Android, which component runs on the main UI thread by default? A) Service B) BroadcastReceiver C) Activity D) AsyncTask.doInBackground() Answer: C Explanation: Activities (and their UI) execute on the main thread unless explicitly moved to a background thread. Question 10. Which Android SDK class provides a mapping from resource IDs to their actual values at runtime? A) Manifest.java B) BuildConfig.java C) R.java D) AndroidManifest.xml Answer: C Explanation: R.java is auto‑generated and contains integer IDs for all resources. Question 11. Which Gradle file defines the application’s compile SDK version, min SDK version, and target SDK version? A) settings.gradle B) gradle.properties C) build.gradle (Module: app) D) AndroidManifest.xml Answer: C
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Explanation: The module‑level build.gradle contains compileSdkVersion, minSdkVersion, and targetSdkVersion. Question 12. In an Android project, where are string resources typically stored? A) res/layout/strings.xml B) res/values/strings.xml C) res/drawable/strings.xml D) assets/strings.xml Answer: B Explanation: res/values/strings.xml holds string resources for localization. Question 13. Which XML attribute defines a view’s width to match the parent’s width? A) android:layout_height="wrap_content" B) android:layout_width="match_parent" C) android:width="fill_parent" D) android:size="match_parent" Answer: B Explanation: android:layout_width="match_parent" makes the view expand to the parent’s width. Question 14. In a LinearLayout, which attribute distributes remaining space proportionally among child views? A) android:layout_gravity B) android:weightSum C) android:layout_weight
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A) RecyclerView B) GridView C) ListView D) ScrollView Answer: C Explanation: ListView works with an Adapter to provide a scrollable list (pre‑RecyclerView). Question 18. Which method is called when a user selects an item from the options menu? A) onCreateOptionsMenu() B) onOptionsItemSelected() C) onPrepareOptionsMenu() D) onMenuItemClick() Answer: B Explanation: onOptionsItemSelected(MenuItem item) handles menu item selections. Question 19. Which Android class is used to display a short, non‑interactive message to the user? A) Snackbar B) AlertDialog C) Toast D) Notification Answer: C Explanation: Toast.makeText(...).show() shows a brief message that fades out automatically.
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Certificate Practice Exam
Question 20. Which preference mode makes the stored data private to the application? A) MODE_WORLD_READABLE B) MODE_WORLD_WRITEABLE C) MODE_PRIVATE D) MODE_MULTI_PROCESS Answer: C Explanation: MODE_PRIVATE (the default) restricts the preferences file to the app’s own process. Question 21. Which method of SharedPreferences.Editor writes changes to disk synchronously? A) apply() B) commit() C) putString() D) clear() Answer: B Explanation: commit() returns a boolean indicating success and blocks until the write completes. Question 22. Which Android permission is required to write to external storage? A) android.permission.READ_EXTERNAL_STORAGE B) android.permission.WRITE_EXTERNAL_STORAGE C) android.permission.INTERNET D) android.permission.ACCESS_NETWORK_STATE Answer: B
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D) create() Answer: A Explanation: insertOrThrow(String table, String nullColumnHack, ContentValues values) inserts a row and throws an exception on failure. Question 26. In Android, which component is best suited for performing a one‑time background download that does not need user interaction? A) Activity B) Service C) BroadcastReceiver D) ContentProvider Answer: B Explanation: A Service can run in the background without a UI, suitable for downloads. Question 27. Which lifecycle method is called when a Service is started with startService()? A) onCreate() B) onStartCommand() C) onBind() D) onDestroy() Answer: B Explanation: onStartCommand() handles each call to startService(). Question 28. What is the purpose of a bound Service? A) To run indefinitely without user interaction
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B) To provide a client‑server interface for components to interact with the Service C) To receive broadcast intents D) To display UI elements from the background Answer: B Explanation: A bound Service allows other components to bind and call its public methods. Question 29. Which manifest element registers a BroadcastReceiver to listen for the device boot completion? A) B) C) D) Answer: C Explanation: <receiver> declares a BroadcastReceiver; the appropriate intent filter would be BOOT_COMPLETED. Question 30. Which method of BroadcastReceiver is invoked when the receiver gets an intent? A) onReceive() B) onStart() C) onCreate() D) onHandleIntent() Answer: A Explanation: onReceive(Context context, Intent intent) handles incoming broadcasts.
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Explanation: onActivityResult(int requestCode, int resultCode, Intent data) processes the returned result. Question 34. In an Activity lifecycle, which callback is guaranteed to be called before the activity becomes visible? A) onPause() B) onStart() C) onDestroy() D) onRestart() Answer: B Explanation: onStart() is invoked after onCreate() and before the activity appears on screen. Question 35. Which method is used to save transient UI state before a configuration change such as rotation? A) onPause() B) onSaveInstanceState() C) onStop() D) onDestroy() Answer: B Explanation: onSaveInstanceState(Bundle outState) stores UI state into the Bundle. Question 36. When an Activity is destroyed due to a configuration change, which method can be used to restore the saved state? A) onRestoreInstanceState() B) onStart()
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C) onCreate() only D) onResume() Answer: A Explanation: onRestoreInstanceState(Bundle savedInstanceState) receives the Bundle after onStart(). Question 37. Which flag added to an Intent starts an Activity in a new task? A) FLAG_ACTIVITY_CLEAR_TOP B) FLAG_ACTIVITY_NEW_TASK C) FLAG_ACTIVITY_SINGLE_TOP D) FLAG_ACTIVITY_REORDER_TO_FRONT Answer: B Explanation: Intent.FLAG_ACTIVITY_NEW_TASK launches the Activity in a separate task stack. Question 38. Which Android component is designed to provide data to other applications via a defined interface? A) Service B) BroadcastReceiver C) ContentProvider D) Activity Answer: C Explanation: ContentProvider abstracts data access and can be shared across apps. Question 39. In Android, which XML element defines a style that can be applied to multiple views?
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Certificate Practice Exam
Question 42. Which view group stacks its children on top of each other? A) LinearLayout B) RelativeLayout C) FrameLayout D) GridLayout Answer: C Explanation: FrameLayout places children in the same frame; later children overlap earlier ones. Question 43. Which layout attribute aligns a child view to the right edge of its parent in a RelativeLayout? A) android:layout_alignParentRight="true" B) android:layout_alignParentEnd="true" C) android:layout_toRightOf="parent" D) android:gravity="right" Answer: A Explanation: layout_alignParentRight positions the view’s right side with the parent’s right side. Question 44. Which method of View can be overridden to handle a custom touch event? A) onClick() B) onTouchEvent() C) onLongClick() D) onKeyDown() Answer: B
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Explanation: onTouchEvent(MotionEvent event) receives raw touch input. Question 45. Which Android class provides a thread pool for executing background tasks without blocking the UI? A) AsyncTask B) HandlerThread C) ExecutorService (via Executors) D) IntentService Answer: C Explanation: ExecutorService (e.g., Executors.newFixedThreadPool) manages a pool of threads. Question 46. Which method of AsyncTask runs on the UI thread after doInBackground() finishes? A) onPreExecute() B) onPostExecute() C) onProgressUpdate() D) onCancelled() Answer: B Explanation: onPostExecute(Result result) receives the background result on the UI thread. Question 47. Which permission must be declared to allow an app to access the device’s location in Android 6.0 and higher? A) android.permission.ACCESS_NETWORK_STATE B) android.permission.ACCESS_FINE_LOCATION
Applications using Java and XML for Mobile
Certificate Practice Exam
Question 50. What is the purpose of the android:exported attribute in a component declaration? A) To indicate whether the component can be launched by other apps B) To set the component’s visibility in the UI C) To define the component’s theme D) To specify the component’s permission level Answer: A Explanation: android:exported="true" allows external apps to invoke the component. Question 51. Which method of Context returns a SharedPreferences instance named “settings”? A) getPreferences("settings") B) getSharedPreferences("settings", MODE_PRIVATE) C) openFileInput("settings") D) getFileStreamPath("settings") Answer: B Explanation: getSharedPreferences(String name, int mode) retrieves a named preference file. Question 52. Which of the following is NOT a valid way to start a Service? A) startService(intent) B) bindService(intent, ServiceConnection, BIND_AUTO_CREATE) C) startActivity(intent) D) ContextCompat.startForegroundService(context, intent) Answer: C
Applications using Java and XML for Mobile
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Explanation: startActivity() launches an Activity, not a Service. Question 53. In Android, which layout parameter is required for a view inside a ConstraintLayout to avoid runtime errors? A) layout_width and layout_height B) layout_constraintStart_toStartOf C) layout_margin D) layout_weight Answer: A Explanation: All views must define layout_width and layout_height; constraints are optional but recommended. Question 54. Which method of Cursor moves the cursor to the first row of the result set? A) moveToFirst() B) first() C) goToFirst() D) position(0) Answer: A Explanation: cursor.moveToFirst() positions the cursor at the first row. Question 55. Which Android class can be used to parse a JSON string into a Java object? A) JSONObject B) XMLPullParser C) SAXParser
