Java Quizz Dive into our tech quiz zone and put your technical skills to the test! Our quizzes cover a wide array of technical topics, perfect for sharpening your knowledge and challenging your understanding. Compete with others, see your rankings, and boost your technical proficiency. Start quizzing today! 1 / 56 1. Which one of the following options correctly describes the behavior of this program? When executed, the program throws an IllegalMonitorStateException. When executed, the program prints “Worker ”, and after that the program hangs (i.e., does not terminate). When executed, the program prints the following: “Worker Master ”. The program does not compile and fails with multiple compiler errors. When executed, the program prints “Worker ” and then terminates. 2 / 56 2. What is the default priority of a thread in Java? 10 1 5 0 3 / 56 3. Which of the following is correct about setFetchSize(int)? None of the above. setFetchSize(int) defines the number of rows that will be read from the database when the ResultSet needs more rows. setFetchSize(int) affects how the database returns the ResultSet data. Both of the above. 4 / 56 4. You cannot use ... inside lambda expressions. arithmetic operations break and continue return statement this keyword 5 / 56 5. What is the maximum number of threads that can be created in a Java program? It depends on the amount of available memory. There is no fixed limit. It depends on the number of CPU cores. It is limited to 100 threads. 6 / 56 6. Which method is used to transform each element of a Stream using a provided function? flatMap map reduce filter 7 / 56 7. Which of the following methods can be used to make a thread pause execution for a specific amount of time? wait() pause() yield() sleep() 8 / 56 8. Select all the classes that extend the String class StringBuilder None StringWriter StringBuffer 9 / 56 9. How can synchronization be achieved in Java threads? Using the volatile keyword. Using the static keyword. Using the synchronized keyword. Using the final keyword. 10 / 56 10. Consider the following program and predict its output:public class Test { public static void main(String[] args) { String str = null; switch (str) { // #1 case "null": System.out.println("null string"); // #2 break; } }} This program results in a compiler error in statement #1. This program results in a compiler error in statement #2. This program results in throwing a NullPointerException. This program prints the following: null string. 11 / 56 11. What is the purpose of the wait() method in Java threads? To pause the execution of a thread. To release the lock held by the thread. To terminate a thread. To notify other threads to resume execution. 12 / 56 12. What is the main purpose of the Stream.sorted method? To reverse the order of elements in the stream To remove duplicate elements from the stream To randomly shuffle the elements of the stream To sort the elements of the stream in their natural order or by a provided comparator 13 / 56 13. Consider the following program:public class StrEqual { public static void main(String[] args) { String s1 = "hello"; String s2 = new String("hello"); String s3 = "hello"; if (s1 == s2) { System.out.println("s1 and s2 equal"); } else { System.out.println("s1 and s2 not equal"); } if (s1 == s3) { System.out.println("s1 and s3 equal"); } else { System.out.println("s1 and s3 not equal"); } }}Which one of the following options provides the output of this program when executed? s1 and s2 equal s1 and s3 not equal s1 and s2 not equal s1 and s3 equal s1 and s2 equal s1 and s3 equal s1 and s2 not equal s1 and s3 not equal 14 / 56 14. What is the output of the following code?int[] arr = {1, 2, 3, 4, 5};System.out.println(arr[2]); 3 4 1 2 15 / 56 15. Consider the following program and predict the output:class MyThread extends Thread { @Override public void run() { System.out.println("In run method; thread name is: " + Thread.currentThread().getName()); }}public class ThreadTest { public static void main(String args[]) { Thread myThread = new MyThread(); myThread.run(); // #1 System.out.println("In main method; thread name is: " + Thread.currentThread().getName()); }} The program results in a runtime exception. The program prints the following: In run method; thread name is: main In main method; thread name is: main The program prints: In the run method; the thread name is: thread-0 In the main method; the thread name is: main The program results in a compiler error at statement #1. 16 / 56 16. Which method is used to start a thread in Java? execute() run() init() start() 17 / 56 17. What is the result of applying the Stream.reduce operation? A list of elements that were reduced A new stream with elements reduced according to a provided accumulator function An Optional describing the reduced value, if any A boolean indicating if any stream elements match a given predicate 18 / 56 18. Which of the following correctly declares an array of integers in Java? int arr = new int[10]; int arr[]; All of the above int[] arr; 19 / 56 19. Which of the following is a checked exception? NullPointerException IOException ArrayIndexOutOfBoundsException ArithmeticException 20 / 56 20. Which method is used to start the execution of a thread? execute() run() begin() start() 21 / 56 21. What is the purpose of the join() method in Java threads? To notify a thread to stop execution. To interrupt the execution of a thread. To wait for a thread to finish its execution. To schedule the execution of a thread. 22 / 56 22. What does the Stream.peek method do? Reduces the stream to a single summary element Filters elements based on a predicate Performs an action on each element of the stream without modifying it Consumes and removes an element from the stream 23 / 56 23. Which method is used to transform each element of a Stream using a provided function? reduce map filter flatMap 24 / 56 24. What will be the output of the below statements?public class Test { public static void main(String[] args) { String s1 = null; System.out.println(s1); //line 2 System.out.println(s1.toString()); //line 3 }} null null NullPointerException NullPointerException null NullPointerException None 25 / 56 25. Which of the following is correct about Statement class of JDBC? Both of the above. none of the above. Statement encapsulates an SQL statement which is passed to the database to be planned and executed. Statement encapsulates an SQL statement which is passed to the database to be parsed and compiled. 26 / 56 26. Which of the following is correct about PreparedStatement? Both of the above. None of the above. Prepared statements are more secure because they use bind variables, which can prevent SQL injection attack. PreparedStatement allows mapping different requests with same prepared statement but different arguments to execute the same execution plan. 27 / 56 27. Which of the following state(s) is/are NOT legitimate thread state(s)? (Select all that apply.) NEW WAITING RUNNABLE TERMINATED EXECUTING 28 / 56 28. Which of the following are valid ChronoUnit values for LocalTime? HALF_DAYS Both B & D NANOS YEAR DAY 29 / 56 29. What type of operation is Stream.filter? Intermediate Source Mutable Terminal 30 / 56 30. Consider the following program and choose the correct answer:class MyThread extends Thread { public MyThread(String name) { this.setName(name); } @Override public void run() { try { sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } play(); } private void play() { System.out.print(getName()); System.out.print(getName()); }}public class ThreadTest { public static void main(String args[]) throws InterruptedException { Thread tableThread = new MyThread("Table"); Thread tennisThread = new MyThread("Tennis"); tableThread.start(); tennisThread.start(); }} The output of this program cannot be predicted; it depends on thread scheduling. This program will always print the following: Table Table Tennis Tennis. This program will always print the following: Tennis Tennis Table Table. This program will throw an IllegalStateException. 31 / 56 31. Which of the following statements are true? A return keyword is always required in a lambda expression Curly brackets are required whenever the return keyword is used in a lambda expression A return keyword is always optional in a lambda expression Lambda expressions don't return values 32 / 56 32. GivenList list = new ArrayList(); // 1list.add(new Integer(2)); // 2list.add(new Object()); // 3Which line will generate a compile-time error? Line marked as // 1 No compile-time error is generated Line marked as // 2 Line marked as // 3 33 / 56 33. Which of the following are valid ChronoField values for LocalDate? Both A & C HOUR_OF_DAY MILLI_OF_SECOND DAY_OF_MONTH DAY_OF_WEEK 34 / 56 34. What is the output of the following program?public class Question { public static void main(String[] args) { Question q = new Question(); List l = new ArrayList(); l.add(20); l.add(30); q.m1(l); } private void m1(List l) { m2(l); // 1 } private void m2(List l) { l.set(1, l.get(0)); // 2 System.out.println(l); }} [20, 20] An exception occurs at runtime Compilation fails on the line marked as // 1 Compilation fails on the line marked as // 2 35 / 56 35. Consider the following program and choose the right option:class MyThread extends Thread { public void run() { System.out.println("Running"); }}public class ThreadTest { public static void main(String args[]) throws InterruptedException { Runnable r = new MyThread(); // #1 Thread myThread = new Thread(r); // #2 myThread.start(); }} The program will compile with no errors but does not print any output in the console. The program will result in a compilation error at statement #2. The program will result in a compilation error at statement #1. The program will compile with no errors and will print “Running” in the console. 36 / 56 36. Consider the following program and predict the output:class MyThread implements Runnable { @Override public void run() { System.out.println(Thread.currentThread().getName()); }}public class ThreadTest { public static void main(String arg[]) { Thread thread = new Thread(new MyThread()); thread.run(); thread.run(); thread.start(); }} Thread-0 Thread-1 Thread-2 Thread-0 main Thread-1 main main Thread-0 main Thread-0 Thread-1 37 / 56 37. Consider the following program and predict the output:class MyThread extends Thread { public MyThread(String name) { this.setName(name); start(); System.out.println("in constructor " + getName()); } @Override public void start() { System.out.println("in start " + getName()); } public void run() { System.out.println("in run " + getName()); }}public class ThreadTest { public static void main(String[] args) { new MyThread("oops"); }} in start oops in run oops in constructor oops in constructor oops in start oops in run oops in start oops in constructor oops in start oops in constructor oops in run oops 38 / 56 38. Which method is used to compare two strings, ignoring case considerations? equals() equalsIgnoreCase() compareTo() compareToIgnoreCase() 39 / 56 39. What is the output of the following code?try { int a = 10 / 0;} catch (ArithmeticException e) { System.out.println("Exception caught");} finally { System.out.println("Finally block");} Exception caught Exception caught Finally block Finally block 40 / 56 40. What is the main advantage of multithreading in Java? Elimination of runtime errors. Improved program performance. Reduced memory usage. Simplified program structure. 41 / 56 41. Consider the following program and predict the output:public class Test { public static void main(String[] args) { String s = new String("5"); System.out.println(1 + 10 + s + 1 + 10); }} 115110 1105110 27 11511 42 / 56 42. Which of the following keywords is used to manually throw an exception? try throws throw catch 43 / 56 43. What is the purpose of the Stream.flatMap method? To map each element to a new value To merge multiple streams into one To replace each element with a stream and then flatten the streams into a single stream To filter elements based on a flat structure 44 / 56 44. Which of the following is a valid lambda expression? All of the above x -> x*x (int x, int y) -> x + y (x, y) -> return x + y; 45 / 56 45. Which of the following type of JDBC driver, uses database native protocol? JDBC-Net, pure Java driver JDBC-ODBC Bridge plus ODBC driver Native-API, partly Java driver Native-protocol, pure Java driver 46 / 56 46. What does the following lambda expression represent?() -> {} A lambda that accepts two parameters and does nothing None of the above A lambda that throws an exception A lambda that does nothing and returns void 47 / 56 47. In which of the following type of ResultSet, the cursor can only move forward in the result set? None of the above. ResultSet.TYPE_SCROLL_SENSITIVE ResultSet.TYPE_SCROLL_INSENSITIVE ResultSet.TYPE_FORWARD_ONLY 48 / 56 48. What will be the output of the following code?String str = "Hello";str.concat(" World");System.out.println(str); Hello Compilation Error World Hello World 49 / 56 49. Lambda expressions can be used with the Java Collections API primarily in ... Filtering Iterating All of the above Sorting 50 / 56 50. Which of these collectors is used for grouping elements of a Stream? Collectors.toSet() Collectors.joining() Collectors.toList() Collectors.groupingBy() 51 / 56 51. Which one of the following classes is best suited for storing timestamp values of application events in a file? java.time.Period class java.time.Instant class java.time.ZoneId class java.time.ZoneOffset class java.time.Duration class 52 / 56 52. Consider this code segment?DateTimeFormatter formatter =DateTimeFormatter.ofPattern("EEEE", Locale.US);System.out.println(formatter.format(LocalDateTime.now()));Which of the following outputs matches the string pattern "EEEE" given in this code segment? September F Friday Sept 53 / 56 53. What is the output of the following program?public class Question { T t; public static void main(String[] args) { Question q = new Question(); // 1 q.t = new Float(1); // 2 System.out.println(q.t); }} 1.0 Compilation fails on the line marked as // 2 Compilation fails on the line marked as // 1 An exception occurs at runtime 54 / 56 54. Which of these is a terminal operation in the Stream API? forEach filter map flatMap 55 / 56 55. Which of the following statements correctly describes the behavior of this program? This program will print 10 in the console. This program will throw a NullPointerException. This program will result in a compiler error. This program will print null in the console. 56 / 56 56. What will be the output of the below statements?public class Test { public static void main(String[] args) { String s1 = "abc"; StringBuffer s2 = new StringBuffer(s1); System.out.println(s1.equals(s2)); }} true Compile-time error false ClassCastException at runtime Your score is 0%
