Practice 70 Java Multithreading Programming Questions

Practice 70 Java Multithreading Programming Questions

Q1. Write a Java program to create a thread that prints "Hello, World!" five times.  
Expected Output:  
Hello, World!  
Hello, World!  
Hello, World!  
Hello, World!  
Hello, World!  

Q2. Write a Java program to create two threads where one thread prints numbers from 1 to 5, and the other thread prints "Java" five times.  
Expected Output:  
1  
2  
3  
4  
5  
Java  
Java  
Java  
Java  
Java  

Q3. Write a Java program to create a thread that prints numbers from 1 to 10 with a 1-second delay between each number.  
Expected Output:  
1 (after 1 second)  
2 (after 1 second)  
3 (after 1 second)  
...  
10  

Q4. Write a Java program to create two threads: one prints "Thread 1" and the other prints "Thread 2" in alternate turns.  
Expected Output:  
Thread 1  
Thread 2  
Thread 1  
Thread 2  
...  

Q5. Write a Java program to demonstrate thread synchronization. Implement two threads that both try to increment a shared variable.  
Expected Output:  
Value of shared variable = 200 (assuming both threads increment it safely)

Q6. Write a Java program to create a thread that prints "Thread Active" five times with a 2-second delay.  
Expected Output:  
Thread Active  
Thread Active  
Thread Active  
Thread Active  
Thread Active  

Q7. Write a Java program to implement a thread that calculates the sum of numbers from 1 to 100.  
Expected Output:  
Sum = 5050  

Q8. Write a Java program to create a thread that prints a Fibonacci sequence up to the 10th term.  
Expected Output:  
0  
1  
1  
2  
3  
5  
8  
13  
21  
34  

Q9. Write a Java program to demonstrate thread communication using `wait()` and `notify()`.  
Expected Output:  
Thread 1 waiting  
Thread 2 notified  

Q10. Write a Java program to create two threads where one thread prints numbers from 1 to 5, and the other prints numbers from 6 to 10.  
Expected Output:  
1  
2  
3  
4  
5  
6  
7  
8  
9  
10  

Q11. Write a Java program to implement a thread that calculates the factorial of a number.  
Input:  
Number = 5  
Expected Output:  
Factorial of 5 = 120  

Q12. Write a Java program to create a thread that prints a countdown from 10 to 1.  
Expected Output:  
10  
9  
8  
7  
6  
5  
4  
3  
2  
1  

Q13. Write a Java program to create a thread that prints the multiplication table of 2.  
Expected Output:  
2 x 1 = 2  
2 x 2 = 4  
2 x 3 = 6  
...  

Q14. Write a Java program to create two threads where one prints "Java" and the other prints "Programming" alternately.  
Expected Output:  
Java  
Programming  
Java  
Programming  
...  

Q15. Write a Java program to create a thread that calculates the sum of squares of numbers from 1 to 5.  
Expected Output:  
Sum of squares = 55  

Q16. Write a Java program to demonstrate thread priorities by creating two threads, one with high priority and the other with low priority.  
Expected Output:  
High-priority thread output first  
Low-priority thread output second  

Q17. Write a Java program to create a thread that prints the first 5 multiples of 3.  
Expected Output:  
3  
6  
9  
12  
15  

Q18. Write a Java program to implement a thread that checks whether a given number is prime.  
Input:  
Number = 7  
Expected Output:  
7 is prime  

Q19. Write a Java program to create a thread that finds the largest number in an array.  
Input:  
Array = [1, 5, 3, 9, 2]  
Expected Output:  
Largest number = 9  

Q20. Write a Java program to create a thread that simulates a task running for 5 seconds, then prints "Task Completed".  
Expected Output:  
Task Completed (after 5 seconds)  

Q21. Write a Java program to create a thread that prints numbers from 1 to 20 with a 0.5-second delay.  
Expected Output:  
1 (after 0.5 second)  
2 (after 0.5 second)  
...  

Q22. Write a Java program to create a thread that reverses a string.  
Input:  
String = "Java"  
Expected Output:  
avaJ  

Q23. Write a Java program to create a thread that calculates the power of a number.  
Input:  
Base = 3, Exponent = 4  
Expected Output:  
3^4 = 81  

Q24. Write a Java program to create a thread that finds the sum of even numbers between 1 and 50.  
Expected Output:  
Sum of even numbers = 650  

Q25. Write a Java program to create two threads: one prints "Task A" and the other prints "Task B" simultaneously.  
Expected Output:  
Task A  
Task B  
(Task A and Task B print alternately)  

Q26. Write a Java program to create a thread that prints all prime numbers between 1 and 50.  
Expected Output:  
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47  

Q27. Write a Java program to create a thread that prints the current system time every second.  
Expected Output:  
Time: [current time] (prints every second)  

Q28. Write a Java program to create a thread that checks if a number is even or odd.  
Input:  
Number = 4  
Expected Output:  
4 is even  

Q29. Write a Java program to implement a thread that checks if a given string is a palindrome.  
Input:  
String = "madam"  
Expected Output:  
madam is a palindrome  

Q30. Write a Java program to create a thread that prints the first 10 numbers of the Fibonacci sequence.  
Expected Output:  
0 1 1 2 3 5 8 13 21 34  

Q31. Write a Java program to create a thread that prints the factorial of a number recursively.  
Input:  
Number = 4  
Expected Output:  
Factorial of 4 = 24  

Q32. Write a Java program to create a thread that prints the sum of digits of a given number.  
Input:  
Number = 123  
Expected Output:  
Sum of digits = 6  

Q33. Write a Java program to create a thread that prints numbers divisible by 3 between 1 and 20.  
Expected Output:  
3 6 9 12 15 18  

Q34. Write a Java program to create a thread that prints the first 5 perfect numbers.  
Expected Output:  
6 28 496 8128 33550336  

Q35. Write a Java program to create a thread that calculates the sum of the first 50 natural numbers.  
Expected Output:  
Sum = 1275  

Q36. Write a Java program to create a thread that calculates the sum of squares of numbers from 1 to 10.  
Expected Output:  
Sum of squares = 385  

Q37. Write a Java program to create a thread that simulates a clock, printing the time every second.  
Expected Output:  
Time: [current time] (prints every second)  

Q38. Write a Java program to implement a thread that simulates a countdown timer from a given number.  
Input:  
Number = 5  
Expected Output:  
5  
4  
3  
2  
1  

Q39. Write a Java program to create a thread that calculates the sum of first 10 odd numbers.  
Expected Output:  
Sum = 100  

Q40. Write a Java program to implement two threads that print numbers from 1 to 10, and the other prints "Java" 10 times.  
Expected Output:  
1  
Java  
2  
Java  
...  

Q41. Write a Java program to create a thread that prints the sum of all multiples of 3 up to 100.  
Expected Output:  
Sum of multiples of 3 = 1683  

Q42. Write a Java program to implement a thread that prints the square root of numbers from 1 to 10.  
Expected Output:  
Square roots = 1.0, 1.414, 1.732, ...  

Q43. Write a Java program to create a thread that prints the sum of numbers from 1 to 50.  
Expected Output:  
Sum = 1275  

Q44. Write a Java program to create a thread that checks whether a given number is a prime number or not.  
Input:  
Number = 11  
Expected Output:  
11 is prime  

Q45. Write a Java program to create a thread that prints "Task Started", waits for 2 seconds, and then prints "Task Ended".  
Expected Output:  
Task Started  
(Task waits for 2 seconds)  
Task Ended  

Q46. Write a Java program to implement a thread that finds the LCM of two numbers.  
Input:  
Number1 = 12, Number2 = 18  
Expected Output:  
LCM = 36  

Q47. Write a Java program to create a thread that prints the reverse of an array of integers.  
Input:  
Array = [1, 2, 3, 4, 5]  
Expected Output:  
[5, 4, 3, 2, 1]  

Q48. Write a Java program to create a thread that prints "Task Completed" after a 5-second delay.  
Expected Output:  
Task Completed (after 5 seconds)  

Q49. Write a Java program to create a thread that prints the first 5 numbers in an arithmetic progression.  
Input:  
Start = 2, Difference = 3  
Expected Output:  
2, 5, 8, 11, 14  

Q50. Write a Java program to create a thread that prints the multiplication table for any number.  
Input:  
Number = 7  
Expected Output:  
7 x 1 = 7  
7 x 2 = 14  
7 x 3 = 21  
...  

Q51. Write a Java program to implement a thread that calculates the sum of squares of numbers from 1 to 10.  
Expected Output:  
Sum of squares = 385  

Q52. Write a Java program to create a thread that prints the first 5 odd numbers.  
Expected Output:  
1  
3  
5  
7  
9  

Q53. Write a Java program to create a thread that checks if a number is divisible by 5.  
Input:  
Number = 10  
Expected Output:  
10 is divisible by 5  

Q54. Write a Java program to create a thread that prints the sum of even numbers from 1 to 100.  
Expected Output:  
Sum of even numbers = 2550  

Q55. Write a Java program to create a thread that prints numbers from 1 to 20 in reverse order.  
Expected Output:  
20  
19  
...  
1  

Q56. Write a Java program to create a thread that calculates the sum of multiples of 4 up to 100.  
Expected Output:  
Sum of multiples of 4 = 1300  

Q57. Write a Java program to create a thread that checks if a number is a perfect number.  
Input:  
Number = 28  
Expected Output:  
28 is a perfect number  

Q58. Write a Java program to create a thread that finds the GCD of two numbers.  
Input:  
Numbers = 24, 36  
Expected Output:  
GCD = 12  

Q59. Write a Java program to create a thread that prints the first 5 prime numbers.  
Expected Output:  
2 3 5 7 11  

Q60. Write a Java program to create a thread that prints numbers divisible by 3 up to 50.  
Expected Output:  
3 6 9 12 15 18 ...  

Q61. Write a Java program to create a thread that prints the first N Fibonacci numbers.  
Input:  
N = 5  
Expected Output:  
0 1 1 2 3  

Q62. Write a Java program to create a thread that calculates the sum of cubes of numbers from 1 to 10.  
Expected Output:  
Sum of cubes = 3025  

Q63. Write a Java program to create a thread that prints a countdown timer every second.  
Expected Output:  
10  
9  
...  
1  

Q64. Write a Java program to create a thread that prints the square of numbers from 1 to 5.  
Expected Output:  
1  
4  
9  
16  
25  

Q65. Write a Java program to create a thread that prints the sum of multiples of 3 and 5 from 1 to 100.  
Expected Output:  
Sum = 2418  

Q66. Write a Java program to implement a thread that finds the factorial of a number.  
Input:  
Number = 6  
Expected Output:  
Factorial of 6 = 720  

Q67. Write a Java program to create a thread that prints all divisors of a given number.  
Input:  
Number = 28  
Expected Output:  
Divisors of 28 = 1 2 4 7 14 28  

Q68. Write a Java program to create a thread that checks if a number is a prime number.  
Input:  
Number = 13  
Expected Output:  
13 is prime  

Q69. Write a Java program to create a thread that prints the even numbers from 1 to 50.  
Expected Output:  
2 4 6 8 ... 50  

Q70. Write a Java program to create a thread that prints the multiplication table of a number.  
Input:  
Number = 6  
Expected Output:  
6 x 1 = 6  
6 x 2 = 12  
...