1. What is the Output?


public class Test {
    public static void main(String[] args) {
        int x = 5;
        System.out.println(x++ + ++x);
    }
}

A. 10
B. 11
C. 12
D. 13

Answer: D

2. Which collection maintains insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. EnumSet

Answer: C

3. Which keyword prevents inheritance?

A. static
B. final
C. abstract
D. volatile

Answer: B

4. What is the output?


String s1 = "Java";
String s2 = new String("Java");
System.out.println(s1 == s2);

A. true
B. false
C. Compile Error
D. Runtime Error

Answer: B

5. Which exception is unchecked?

A. IOException
B. SQLException
C. NullPointerException
D. FileNotFoundException

Answer: C

6. What is the default value of boolean?

A. true
B. false
C. null
D. 0

Answer: B

7. Which interface is implemented by ArrayList?

A. Set
B. Queue
C. List
D. Map

Answer: C

8. Output?


System.out.println(10 + 20 + "Java");

A. Java1020
B. 30Java
C. 1020Java
D. Error

Answer: B

9. Which Java feature supports runtime polymorphism?

A. Method Overloading
B. Method Overriding
C. Constructor
D. Encapsulation

Answer: B

10. Which package contains Scanner?

A. java.lang
B. java.io
C. java.util
D. java.net

Answer: C

Java Hard Level MCQ Set-2 (11-20)

11. Output?


int a = 10;
int b = 20;
System.out.println(a > b ? a : b);

A. 10
B. 20
C. Error
D. 0

Answer: B

12. Which class is immutable?

A. StringBuilder
B. StringBuffer
C. String
D. Date

Answer: C

13. Which collection allows duplicate elements?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. ArrayList

Answer: D

14. What is JVM?

A. Java Virtual Machine
B. Java Variable Method
C. Java Verified Machine
D. Java View Model

Answer: A

15. Which access modifier gives maximum accessibility?

A. private
B. protected
C. default
D. public

Answer: D

16. Output?


System.out.println(5/2);

A. 2
B. 2.5
C. 3
D. Error

Answer: A

17. Which class cannot be instantiated?

A. Final Class
B. Abstract Class
C. Static Class
D. Inner Class

Answer: B

18. Which collection sorts elements automatically?

A. HashSet
B. ArrayList
C. TreeSet
D. LinkedList

Answer: C

19. Which keyword is used for inheritance?

A. implement
B. inherits
C. extends
D. super

Answer: C

20. Which method starts a thread?

A. run()
B. execute()
C. start()
D. init()

Answer: C

Hard Coding MCQ Example

21. Output?


class A{
    static{
        System.out.print("A");
    }
}
public class Test{
    public static void main(String[] args){
        A obj = new A();
    }
}

A. A
B. AA
C. Compile Error
D. Runtime Error

Answer: A

22. Output?


String str = null;
System.out.println(str instanceof String);

A. true
B. false
C. Exception
D. Error

Answer: B

23. Output?


System.out.println('A' + 1);

A. A1
B. B
C. 66
D. Error

Answer: C

24. Output?


Integer a = 100;
Integer b = 100;
System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

Answer: A

25. Which class is thread-safe?

A. StringBuilder
B. ArrayList
C. HashMap
D. StringBuffer

Answer: D

Java Hard Level MCQ Set-3 (26–50)

26. Output?


System.out.println(10 + 20 + "30" + 40);

A. 10203040
B. 303040
C. 302040
D. 3040

Answer: B

27. Output?


int x = 5;
System.out.println(x++ + x++);

A. 10
B. 11
C. 12
D. 13

Answer: B

28. Which collection does NOT allow duplicate keys?

A. List
B. Set
C. Map
D. Queue

Answer: C

29. Output?


String s = "Java";
s.concat(" Programming");
System.out.println(s);

A. Java Programming
B. Programming
C. Java
D. Error

Answer: C

30. Which keyword refers to parent class constructor?

A. this
B. parent
C. super
D. extends

Answer: C

31. Output?


int a = 10;
System.out.println(a += a -= a *= 2);

A. 0
B. 10
C. 20
D. 30

Answer: B

32. Which class is used for dynamic string modification?

A. String
B. Character
C. StringBuilder
D. Math

Answer: C

33. Output?


System.out.println(0.1 + 0.2 == 0.3);

A. true
B. false
C. Error
D. Exception

Answer: B

34. Which interface supports lambda expressions?

A. Marker Interface
B. Functional Interface
C. Serializable
D. Cloneable

Answer: B

35. Output?


int[] arr = {1,2,3};
System.out.println(arr[3]);

A. 3
B. 0
C. Compile Error
D. ArrayIndexOutOfBoundsException

Answer: D

36. Output?


String s1 = "Java";
String s2 = "Java";
System.out.println(s1 == s2);

A. true
B. false
C. Error
D. Exception

Answer: A

37. Which exception occurs when dividing by zero?

A. ArithmeticException
B. IOException
C. NullPointerException
D. SQLException

Answer: A

38. Output?


int x = 10;
System.out.println(++x + x++);

A. 21
B. 22
C. 23
D. 24

Answer: B

39. Which collection stores key-value pairs?

A. Set
B. List
C. Queue
D. Map

Answer: D

40. Output?


System.out.println("Java".substring(1,3));

A. av
B. ava
C. va
D. Jav

Answer: A

41. Which keyword is used to create a constant?

A. static
B. const
C. final
D. fixed

Answer: C

42. Output?


Integer a = 128;
Integer b = 128;
System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

Answer: B

43. Which collection is synchronized by default?

A. ArrayList
B. Vector
C. HashSet
D. HashMap

Answer: B

44. Output?


String s = "";
System.out.println(s.length());

A. 0
B. 1
C. null
D. Error

Answer: A

45. Which method is called automatically by garbage collector?

A. destroy()
B. finalize()
C. clean()
D. gc()

Answer: B

46. Output?


System.out.println(5 + 'A');

A. A5
B. 70
C. 65
D. Error

Answer: B

47. Which Java feature hides implementation details?

A. Inheritance
B. Encapsulation
C. Polymorphism
D. Overloading

Answer: B

48. Output?


StringBuilder sb = new StringBuilder("Java");
sb.reverse();
System.out.println(sb);

A. Java
B. avaJ
C. JAVA
D. Error

Answer: B

49. Which collection provides FIFO behavior?

A. Stack
B. Queue
C. Set
D. Map

Answer: B

50. Output?


try {
    System.out.print("A");
    int x = 10/0;
} catch(Exception e) {
    System.out.print("B");
} finally {
    System.out.print("C");
}

A. ABC
B. AC
C. BC
D. ABCD

Answer: A

Java Hard Level MCQ Set-4 (51–75)

51. Output?


int x = 1;
int y = x++ + ++x;
System.out.println(y);

A. 2
B. 3
C. 4
D. 5

✅ Answer: C

52. Which collection allows one null key?

A. TreeMap
B. Hashtable
C. HashMap
D. ConcurrentHashMap

✅ Answer: C

53. Output?


System.out.println(10 * 20 + "Java");

A. 1020Java
B. 200Java
C. Java200
D. Error

✅ Answer: B

54. Which keyword is used to inherit an interface?

A. extend
B. extends
C. implements
D. inherit

✅ Answer: C

55. Output?


String str = "Java";
System.out.println(str.charAt(2));

A. J
B. a
C. v
D. Error

✅ Answer: C

56. Which class is NOT part of Collection Framework?

A. ArrayList
B. HashSet
C. HashMap
D. Arrays

✅ Answer: D

57. Output?


System.out.println(11 % 3);

A. 3
B. 2
C. 1
D. 0

✅ Answer: B

58. Which Java 8 feature enables functional programming?

A. Lambda Expressions
B. Packages
C. Threads
D. Applets

✅ Answer: A

59. Output?


String s = "JAVA";
System.out.println(s.toLowerCase());

A. JAVA
B. java
C. Java
D. Error

✅ Answer: B

60. Which collection sorts keys?

A. HashMap
B. LinkedHashMap
C. TreeMap
D. Hashtable

✅ Answer: C

61. Output?


int a = 5;
System.out.println(a++ + ++a + a);

A. 17
B. 18
C. 19
D. 20

✅ Answer: B

62. Which exception occurs when a string is converted to an invalid number?

A. IOException
B. NumberFormatException
C. SQLException
D. ArithmeticException

✅ Answer: B

63. Output?


String s = "Java";
System.out.println(s.replace('a','x'));

A. Jxvx
B. Jxva
C. Java
D. Error

✅ Answer: A

64. Which keyword prevents method overriding?

A. static
B. final
C. private
D. protected

✅ Answer: B

65. Output?


System.out.println(Math.max(15,20));

A. 15
B. 20
C. 35
D. Error

✅ Answer: B

66. Which collection is best for unique sorted elements?

A. ArrayList
B. LinkedList
C. TreeSet
D. Vector

✅ Answer: C

67. Output?


String s = "Java";
System.out.println(s.indexOf('v'));

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

68. Which package contains Stream API?

A. java.util.stream
B. java.io.stream
C. java.lang.stream
D. java.net.stream

✅ Answer: A

69. Output?


int x = 7;
System.out.println(x>>1);

A. 7
B. 3
C. 14
D. 1

✅ Answer: B

70. Which interface is used for sorting custom objects?

A. Serializable
B. Runnable
C. Comparable
D. Cloneable

✅ Answer: C

71. Output?


String s = "Java";
System.out.println(s.startsWith("Ja"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

72. Which method removes leading and trailing spaces?

A. cut()
B. trim()
C. remove()
D. stripAll()

✅ Answer: B

73. Output?


int x = 2;
System.out.println(x<<2);

A. 4
B. 6
C. 8
D. 16

✅ Answer: C

74. Which class is used to read user input?

A. System
B. Scanner
C. Reader
D. ConsoleReader

✅ Answer: B

75. Output?


String s = "JAVA";
System.out.println(s.equalsIgnoreCase("java"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

Super Tricky YouTube Shorts Question #76


Integer a = 127;
Integer b = 127;

System.out.println(a == b);

A. true
B. false
C. Compile Error
D. Runtime Error

✅ Answer: A

#77


Integer a = 128;
Integer b = 128;

System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

✅ Answer: B

78. Which interface is a Functional Interface?

A. Runnable
B. Serializable
C. Cloneable
D. Comparable

✅ Answer: A

79. Output?


String s1 = new String("Java");
String s2 = new String("Java");

System.out.println(s1.equals(s2));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

80. Which Java feature allows same method name with different parameters?

A. Overriding
B. Encapsulation
C. Overloading
D. Abstraction

✅ Answer: C

81. Output?


System.out.println(5 + 2 * 3);

A. 21
B. 11
C. 15
D. 13

✅ Answer: B

82. Which collection is NOT synchronized?

A. Vector
B. Hashtable
C. ArrayList
D. Stack

✅ Answer: C

83. Output?


String s = "Java";
s = s.concat("8");
System.out.println(s);

A. Java
B. 8
C. Java8
D. Error

✅ Answer: C

84. Which keyword is used for abstraction?

A. final
B. abstract
C. static
D. volatile

✅ Answer: B

85. Output?


System.out.println(10 + 20 * 2);

A. 60
B. 50
C. 40
D. 30

✅ Answer: B

86. Which class is thread-safe?

A. StringBuilder
B. HashMap
C. StringBuffer
D. ArrayList

✅ Answer: C

87. Output?


int x = 5;
System.out.println(x++ + ++x + x++);

A. 17
B. 18
C. 19
D. 20

✅ Answer: B

88. Which exception is thrown by Thread.sleep()?

A. IOException
B. InterruptedException
C. SQLException
D. RuntimeException

✅ Answer: B

89. Output?


System.out.println(Math.min(10,20));

A. 10
B. 20
C. 30
D. Error

✅ Answer: A

90. Which interface provides natural ordering?

A. Comparator
B. Comparable
C. Serializable
D. Cloneable

✅ Answer: B

91. Output?


String s = "Java";
System.out.println(s.substring(2));

A. Ja
B. va
C. ava
D. Java

✅ Answer: B

92. Which collection uses Red-Black Tree internally?

A. HashSet
B. TreeMap
C. LinkedList
D. Vector

✅ Answer: B

93. Output?


System.out.println(10/3);

A. 3.33
B. 3
C. 4
D. Error

✅ Answer: B

94. Which method is used to create Stream from List?

A. getStream()
B. stream()
C. createStream()
D. listStream()

✅ Answer: B

95. Output?


String s = "Java";
System.out.println(s.contains("av"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

96. Which collection allows duplicate values but unique keys?

A. Set
B. Map
C. Queue
D. Stack

✅ Answer: B

97. Output?


System.out.println(5 > 3 ? "Yes" : "No");

A. Yes
B. No
C. Error
D. Exception

✅ Answer: A

98. Which Java 8 class helps avoid NullPointerException?

A. Optional
B. Stream
C. Lambda
D. Predicate

✅ Answer: A

99. Output?


int a = 1;
int b = 2;
int c = 3;

System.out.println(a + b * c);

A. 9
B. 7
C. 6
D. 5

✅ Answer: B

100. Output?


String s = "JAVA";
System.out.println(s.toLowerCase().toUpperCase());

A. java
B. JAVA
C. Java
D. Error

✅ Answer: B

Java Hard Level MCQ Set-6 (101–125)

101. Output?


int x = 10;
System.out.println(x++ + x++ + ++x);

A. 32
B. 33
C. 34
D. 35

✅ Answer: C

102. Which class is immutable?

A. StringBuilder
B. StringBuffer
C. String
D. Date

✅ Answer: C

103. Output?


String s = "Java";
System.out.println(s.length());

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

104. Which collection preserves insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

105. Output?


System.out.println(10 + 5 * 2 - 3);

A. 17
B. 20
C. 15
D. 25

✅ Answer: A

106. What is the size of byte in Java?

A. 4 bits
B. 8 bits
C. 16 bits
D. 32 bits

✅ Answer: B

107. Output?


String str = "Java";
System.out.println(str.toUpperCase());

A. java
B. JAVA
C. Java
D. Error

✅ Answer: B

108. Which collection does not allow duplicates?

A. List
B. Queue
C. Set
D. Vector

✅ Answer: C

109. Output?


int a = 5;
int b = 10;
System.out.println(a > b);

A. true
B. false
C. Error
D. Exception

✅ Answer: B

110. Which keyword is used to inherit a class?

A. implement
B. extends
C. inherit
D. super

✅ Answer: B

111. Output?


System.out.println(25 % 4);

A. 0
B. 1
C. 2
D. 3

✅ Answer: B

112. Which method converts String to int?

A. Integer.parseInt()
B. Integer.value()
C. String.toInt()
D. parse()

✅ Answer: A

113. Output?


String s = "Java";
System.out.println(s.charAt(0));

A. a
B. J
C. v
D. Error

✅ Answer: B

114. Which exception occurs when accessing invalid array index?

A. ArithmeticException
B. ArrayIndexOutOfBoundsException
C. NullPointerException
D. IOException

✅ Answer: B

115. Output?


System.out.println(7 / 2);

A. 3
B. 3.5
C. 4
D. Error

✅ Answer: A

116. Which interface is implemented by ArrayList?

A. Set
B. Queue
C. List
D. Map

✅ Answer: C

117. Output?


String s1 = "Java";
String s2 = "Java";

System.out.println(s1.equals(s2));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

118. Which method starts a thread?

A. run()
B. start()
C. execute()
D. begin()

✅ Answer: B

119. Output?


System.out.println(Math.sqrt(81));

A. 8
B. 9
C. 10
D. Error

✅ Answer: B

120. Which collection is based on FIFO?

A. Stack
B. Queue
C. Set
D. Map

✅ Answer: B

121. Output?


int x = 4;
System.out.println(x << 1);

A. 4
B. 8
C. 16
D. 2

✅ Answer: B

122. Which keyword is used for method overriding restriction?

A. static
B. abstract
C. final
D. volatile

✅ Answer: C

123. Output?


System.out.println("Java".replace('a','o'));

A. Jovo
B. Java
C. Jova
D. Error

✅ Answer: A

124. Which package contains ArrayList?

A. java.lang
B. java.util
C. java.io
D. java.net

✅ Answer: B

125. Output?


String s = "Java";
System.out.println(s.endsWith("va"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

Java Hard Level MCQ Set-7 (126–150)

126. Output?


int a = 5;
int b = 10;
int c = a + b * 2;
System.out.println(c);

A. 25
B. 30
C. 20
D. 15

✅ Answer: A

127. Which collection maintains insertion order and allows duplicates?

A. HashSet
B. TreeSet
C. ArrayList
D. PriorityQueue

✅ Answer: C

128. Output?


String str = "JAVA";
System.out.println(str.toLowerCase());

A. JAVA
B. java
C. Java
D. Error

✅ Answer: B

129. Which access modifier is visible only within the same class?

A. public
B. protected
C. default
D. private

✅ Answer: D

130. Output?


System.out.println(15 / 4);

A. 3
B. 3.75
C. 4
D. Error

✅ Answer: A

131. Which class is synchronized?

A. ArrayList
B. HashMap
C. Vector
D. HashSet

✅ Answer: C

132. Output?


String s = "Java";
System.out.println(s.substring(1));

A. ava
B. Jav
C. va
D. Error

✅ Answer: A

133. Which interface is used in lambda expressions?

A. Functional Interface
B. Marker Interface
C. Serializable
D. Cloneable

✅ Answer: A

134. Output?


int x = 3;
System.out.println(++x * 2);

A. 6
B. 7
C. 8
D. 9

✅ Answer: C

135. Which exception is unchecked?

A. IOException
B. SQLException
C. ClassNotFoundException
D. NullPointerException

✅ Answer: D

136. Output?


String s = "";
System.out.println(s.isEmpty());

A. true
B. false
C. Error
D. Exception

✅ Answer: A

137. Which collection automatically sorts elements?

A. LinkedList
B. ArrayList
C. TreeSet
D. Vector

✅ Answer: C

138. Output?


System.out.println(Math.pow(2,3));

A. 6
B. 8.0
C. 8
D. Error

✅ Answer: B

139. Which keyword is used to call parent class method?

A. this
B. super
C. extends
D. parent

✅ Answer: B

140. Output?


String s = "Java";
System.out.println(s.contains("Ja"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

141. Which collection allows only unique elements?

A. List
B. Queue
C. Set
D. Vector

✅ Answer: C

142. Output?


int x = 8;
System.out.println(x >> 2);

A. 1
B. 2
C. 4
D. 8

✅ Answer: B

143. Which class is used for mutable strings?

A. String
B. StringBuilder
C. Character
D. Object

✅ Answer: B

144. Output?


String s = "Programming";
System.out.println(s.length());

A. 10
B. 11
C. 12
D. 13

✅ Answer: B

145. Which collection stores elements in key-value format?

A. Set
B. List
C. Queue
D. Map

✅ Answer: D

146. Output?


System.out.println(20 % 6);

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

147. Which method is used to compare String values?

A. ==
B. compare()
C. equals()
D. match()

✅ Answer: C

148. Output?


String s = "JAVA";
System.out.println(s.charAt(3));

A. J
B. A
C. V
D. Error

✅ Answer: B

149. Which package contains Scanner class?

A. java.io
B. java.lang
C. java.util
D. java.net

✅ Answer: C

150. Output?


int x = 5;
System.out.println(x++ + ++x + ++x);

A. 18
B. 19
C. 20
D. 21

✅ Answer: B

Java Hard Level MCQ Set-8 (151–175)

151. Output?


int x = 2;
System.out.println(x++ + ++x + x++);

A. 8
B. 9
C. 10
D. 11

✅ Answer: A

Explanation:

x++ → 2 (x=3)
++x → 4
x++ → 4 (x=5)

Result = 2 + 4 + 4 = 10

⚠️ Correct Answer actually C (10) hai.

152. Which collection is NOT ordered?

A. ArrayList
B. LinkedList
C. HashSet
D. Vector

✅ Answer: C

153. Output?


String s = "Java";
System.out.println(s.indexOf('a'));

A. 0
B. 1
C. 2
D. 3

✅ Answer: B

154. Which class is used to create threads?

A. Thread
B. Runnable
C. Executor
D. Process

✅ Answer: A

155. Output?


System.out.println(17 / 5);

A. 3
B. 3.4
C. 4
D. Error

✅ Answer: A

156. Which collection is based on a hash table?

A. TreeMap
B. HashMap
C. LinkedList
D. Vector

✅ Answer: B

157. Output?


String s = "Programming";
System.out.println(s.substring(3,7));

A. gram
B. gramm
C. ogra
D. grami

✅ Answer: A

158. Which keyword is used to stop inheritance?

A. static
B. final
C. abstract
D. private

✅ Answer: B

159. Output?


System.out.println(Math.abs(-25));

A. -25
B. 25
C. 0
D. Error

✅ Answer: B

160. Which interface is implemented by HashSet?

A. List
B. Queue
C. Set
D. Map

✅ Answer: C

161. Output?


String s = "Java";
System.out.println(s.replace("a","x"));

A. Jxvx
B. Jxva
C. Java
D. Error

✅ Answer: A

162. Which exception occurs when dividing an integer by zero?

A. IOException
B. ArithmeticException
C. SQLException
D. RuntimeException

✅ Answer: B

163. Output?


int x = 10;
System.out.println(--x + x--);

A. 17
B. 18
C. 19
D. 20

✅ Answer: B

164. Which collection maintains insertion order of keys?

A. HashMap
B. Hashtable
C. TreeMap
D. LinkedHashMap

✅ Answer: D

165. Output?


String s = "JAVA";
System.out.println(s.equals("java"));

A. true
B. false
C. Error
D. Exception

✅ Answer: B

166. Which method is used to terminate a thread?

A. stop()
B. destroy()
C. exit()
D. kill()

✅ Answer: A (deprecated)

167. Output?


System.out.println(9 % 2);

A. 0
B. 1
C. 2
D. 9

✅ Answer: B

168. Which collection allows duplicate elements?

A. Set
B. TreeSet
C. HashSet
D. ArrayList

✅ Answer: D

169. Output?


String s = "Java";
System.out.println(s.toUpperCase().length());

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

170. Which package contains HashMap?

A. java.io
B. java.lang
C. java.util
D. java.net

✅ Answer: C

171. Output?


Integer a = 100;
Integer b = 100;

System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

172. Which Java feature allows one interface to have multiple implementations?

A. Encapsulation
B. Polymorphism
C. Abstraction
D. Inheritance

✅ Answer: B

173. Output?


StringBuilder sb = new StringBuilder("Java");
sb.append("8");

System.out.println(sb);

A. Java
B. Java8
C. 8Java
D. Error

✅ Answer: B

174. Which collection sorts elements naturally?

A. ArrayList
B. LinkedList
C. TreeSet
D. Vector

✅ Answer: C

175. Output?


int x = 1;

for(int i=1;i<=3;i++)
{
    x *= 2;
}

System.out.println(x);

A. 4
B. 6
C. 8
D. 16

✅ Answer: C

Java Expert Level MCQ Set-9 (176–200)

176. Output?


int x = 5;
System.out.println(x++ + ++x + --x);

A. 17
B. 18
C. 19
D. 20

✅ Answer: B

Explanation:

x++ → 5 (x=6)
++x → 7 (x=7)
--x → 6 (x=6)

Result = 5 + 7 + 6 = 18

177. What will happen?


ArrayList<String> list = new ArrayList<>();
list.add("Java");
list.add(null);

System.out.println(list.size());

A. Compile Error
B. Runtime Error
C. 1
D. 2

✅ Answer: D

178. Output?


String s = "Java";
System.out.println(s.substring(1, 4));

A. ava
B. Jav
C. va
D. Error

✅ Answer: A

179. Which collection allows one null key and multiple null values?

A. Hashtable
B. TreeMap
C. HashMap
D. ConcurrentHashMap

✅ Answer: C

180. Output?


System.out.println(Math.ceil(10.1));

A. 10
B. 11.0
C. 11
D. 10.1

✅ Answer: B

181. Output?


String s1 = "Java";
String s2 = "Ja" + "va";

System.out.println(s1 == s2);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

182. Which interface is used by lambda expressions?

A. Marker Interface
B. Functional Interface
C. Serializable
D. Cloneable

✅ Answer: B

183. Output?


System.out.println(10 >> 1);

A. 10
B. 5
C. 20
D. 2

✅ Answer: B

184. Which method is used to obtain current thread?

A. current()
B. getThread()
C. currentThread()
D. thread()

✅ Answer: C

185. Output?


String s = "Java";
System.out.println(s.concat("8"));

A. Java
B. Java8
C. 8Java
D. Error

✅ Answer: B

186. Which exception is unchecked?

A. IOException
B. SQLException
C. FileNotFoundException
D. ArithmeticException

✅ Answer: D

187. Output?


Integer a = 127;
Integer b = 127;

System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

188. Output?


Integer a = 128;
Integer b = 128;

System.out.println(a == b);

A. true
B. false
C. Error
D. Exception

✅ Answer: B

189. Which collection automatically sorts elements?

A. ArrayList
B. LinkedList
C. TreeSet
D. HashSet

✅ Answer: C

190. Output?


System.out.println("Java".compareTo("Java"));

A. 1
B. -1
C. 0
D. Error

✅ Answer: C

191. What is the output?


try {
    int x = 10 / 0;
} catch (Exception e) {
    System.out.print("A");
} finally {
    System.out.print("B");
}

A. A
B. B
C. AB
D. BA

✅ Answer: C

192. Which Stream operation is intermediate?

A. collect()
B. forEach()
C. filter()
D. count()

✅ Answer: C

193. Output?


System.out.println(Math.max(25, 30));

A. 25
B. 30
C. 55
D. Error

✅ Answer: B

194. Which class is immutable?

A. StringBuilder
B. StringBuffer
C. String
D. Date

✅ Answer: C

195. Output?


StringBuilder sb = new StringBuilder("Java");
sb.reverse();

System.out.println(sb);

A. avaJ
B. JAVA
C. Java
D. Error

✅ Answer: A

196. Which collection preserves insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

197. Output?


System.out.println(5 + 3 * 2);

A. 16
B. 11
C. 10
D. 13

✅ Answer: B

198. Which method creates a Stream from a List?

A. getStream()
B. stream()
C. createStream()
D. makeStream()

✅ Answer: B

199. Output?


String s = null;
System.out.println(String.valueOf(s));

A. null
B. Exception
C. ""
D. Error

✅ Answer: A

200. Output?


List<Integer> list =
Arrays.asList(1,2,3,4,5);

long count = list.stream()
                 .filter(x -> x % 2 == 0)
                 .count();

System.out.println(count);

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

Java Expert Level MCQ Set-10 (201–225)

201. Output?


Thread t = new Thread();
System.out.println(t.isAlive());

A. true
B. false
C. Compile Error
D. Runtime Error

✅ Answer: B

202. Which method starts a new thread?

A. run()
B. start()
C. execute()
D. begin()

✅ Answer: B

203. Output?


Runnable r = () -> System.out.print("Java");
r.run();

A. Java
B. Compile Error
C. Runtime Error
D. Nothing

✅ Answer: A

204. Which interface can return a value from a thread?

A. Runnable
B. Callable
C. Thread
D. Supplier

✅ Answer: B

205. Output?


System.out.println(
    java.util.Optional.ofNullable(null)
                      .orElse("Java")
);

A. null
B. Java
C. Exception
D. Error

✅ Answer: B

206. Which class manages thread pools?

A. ThreadManager
B. ExecutorService
C. PoolExecutor
D. ThreadPool

✅ Answer: B

207. Output?


List<Integer> list =
Arrays.asList(1,2,3,4,5);

list.stream()
    .filter(x -> x % 2 == 1)
    .forEach(System.out::print);

A. 12345
B. 135
C. 24
D. Error

✅ Answer: B

208. Which collection is thread-safe?

A. HashMap
B. ArrayList
C. ConcurrentHashMap
D. LinkedList

✅ Answer: C

209. Output?


System.out.println(
    java.util.stream.Stream.of(1,2,3)
        .map(x -> x * 2)
        .count()
);

A. 3
B. 6
C. 12
D. Error

✅ Answer: A

210. Which Stream method produces a single result?

A. filter()
B. map()
C. sorted()
D. reduce()

✅ Answer: D

211. Output?


String str = "Java";

System.out.println(
    str.chars().count()
);

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

212. Which class is used for immutable date-time API in Java 8?

A. Date
B. Calendar
C. LocalDate
D. Timestamp

✅ Answer: C

213. Output?


System.out.println(
    java.util.Optional.of("Java")
        .get()
);

A. Java
B. null
C. Exception
D. Error

✅ Answer: A

214. Which exception is thrown by Optional.get() when empty?

A. NullPointerException
B. NoSuchElementException
C. IOException
D. IllegalStateException

✅ Answer: B

215. Output?


List<String> list =
Arrays.asList("A","B","C");

System.out.println(
    list.stream().findFirst().get()
);

A. A
B. B
C. C
D. Error

✅ Answer: A

216. Which keyword ensures visibility across threads?

A. static
B. synchronized
C. volatile
D. transient

✅ Answer: C

217. Output?


System.out.println(
    java.util.stream.Stream.of(
        "Java","Python","C"
    ).sorted().findFirst().get()
);

A. Java
B. Python
C. C
D. Error

✅ Answer: C

218. Which collection allows concurrent updates without full locking?

A. Hashtable
B. HashMap
C. ConcurrentHashMap
D. TreeMap

✅ Answer: C

219. Output?


List<Integer> list =
Arrays.asList(1,2,3);

int sum = list.stream()
              .reduce(0, Integer::sum);

System.out.println(sum);

A. 3
B. 5
C. 6
D. 7

✅ Answer: C

220. Which method submits Callable tasks?

A. start()
B. execute()
C. submit()
D. invoke()

✅ Answer: C

221. Output?


Future<Integer> f =
Executors.newSingleThreadExecutor()
         .submit(() -> 10);

System.out.println(f.get());

A. 0
B. 1
C. 10
D. Compile Error

✅ Answer: C

222. Which class is part of java.time package?

A. Date
B. Calendar
C. LocalTime
D. Timestamp

✅ Answer: C

223. Output?


List<Integer> nums =
Arrays.asList(10,20,30);

System.out.println(
nums.stream()
    .mapToInt(Integer::intValue)
    .sum()
);

A. 50
B. 60
C. 70
D. 80

✅ Answer: B

224. Which Stream operation is terminal?

A. map()
B. filter()
C. sorted()
D. collect()

✅ Answer: D

225. Output?


System.out.println(
java.util.Optional
.ofNullable(null)
.isPresent()
);

A. true
B. false
C. null
D. Error

✅ Answer: B

Java Expert Level MCQ Set-11 (226–250)

226. Output?


HashMap<Integer, String> map = new HashMap<>();

map.put(1, "Java");
map.put(1, "Python");

System.out.println(map.get(1));

A. Java
B. Python
C. null
D. Error

✅ Answer: B

227. Which interface is implemented by HashMap?

A. List
B. Set
C. Map
D. Queue

✅ Answer: C

228. Output?


System.out.println(
    java.util.stream.Stream.of(1,2,3,4)
        .filter(x -> x > 2)
        .count()
);

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

229. Which class is thread-safe?

A. HashMap
B. ArrayList
C. Vector
D. LinkedList

✅ Answer: C

230. Output?


List<String> list =
Arrays.asList("Java","Python");

System.out.println(
    list.stream()
        .findAny()
        .get()
);

A. Java
B. Python
C. Java or Python
D. Error

✅ Answer: C

231. Which keyword prevents variable value modification?

A. static
B. final
C. transient
D. volatile

✅ Answer: B

232. Output?


System.out.println(
    java.util.Optional.empty()
        .orElse("Default")
);

A. null
B. Default
C. Error
D. Exception

✅ Answer: B

233. Which collection maintains insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

234. Output?


System.out.println(
    java.util.stream.Stream.of(1,2,3)
        .reduce(0, Integer::sum)
);

A. 3
B. 5
C. 6
D. 7

✅ Answer: C

235. Which exception occurs when calling `next()` on an empty Iterator?

A. IOException
B. NoSuchElementException
C. NullPointerException
D. IllegalStateException

✅ Answer: B

236. Output?


List<Integer> list =
Arrays.asList(5,10,15);

System.out.println(
    list.stream()
        .max(Integer::compare)
        .get()
);

A. 5
B. 10
C. 15
D. Error

✅ Answer: C

237. Which collection sorts keys automatically?

A. HashMap
B. LinkedHashMap
C. TreeMap
D. Hashtable

✅ Answer: C

238. Output?


String s = "Java";

System.out.println(
    s.repeat(2)
);

A. Java
B. JavaJava
C. 2Java
D. Error

✅ Answer: B

239. Which Java 8 interface represents a boolean-valued function?

A. Function
B. Consumer
C. Supplier
D. Predicate

✅ Answer: D

240. Output?


System.out.println(
    java.util.stream.Stream.of("A","B","C")
        .count()
);

A. 2
B. 3
C. 4
D. Error

✅ Answer: B

241. Which class provides atomic operations?

A. AtomicInteger
B. Integer
C. Number
D. Math

✅ Answer: A

242. Output?


AtomicInteger ai =
new AtomicInteger(5);

System.out.println(
    ai.incrementAndGet()
);

A. 5
B. 6
C. 7
D. Error

✅ Answer: B

243. Which method waits for thread completion?

A. stop()
B. sleep()
C. join()
D. wait()

✅ Answer: C

244. Output?


String s = "JAVA";

System.out.println(
    s.toLowerCase()
);

A. JAVA
B. Java
C. java
D. Error

✅ Answer: C

245. Which collection allows duplicate elements?

A. Set
B. TreeSet
C. HashSet
D. ArrayList

✅ Answer: D

246. Output?


System.out.println(
    java.util.Optional.of("Java")
        .map(String::length)
        .get()
);

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

247. Which Stream method transforms elements?

A. filter()
B. count()
C. map()
D. collect()

✅ Answer: C

248. Output?


List<Integer> list =
Arrays.asList(2,4,6);

boolean result =
list.stream()
    .allMatch(x -> x % 2 == 0);

System.out.println(result);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

249. Which keyword is used for synchronization?

A. volatile
B. synchronized
C. transient
D. strictfp

✅ Answer: B

250. Output?


System.out.println(
    java.util.stream.Stream.of(10,20,30)
        .mapToInt(Integer::intValue)
        .average()
        .getAsDouble()
);

A. 10.0
B. 20.0
C. 30.0
D. 60.0

✅ Answer: B

Java Expert Level MCQ Set-12 (251–275)

251. Output?


System.out.println(0.1 + 0.2 == 0.3);

A. true
B. false
C. Compile Error
D. Runtime Error

✅ Answer: B

252. Which class is used for concurrent thread-safe map?

A. HashMap
B. TreeMap
C. ConcurrentHashMap
D. LinkedHashMap

✅ Answer: C

253. Output?


List<Integer> list = Arrays.asList(1,2,3,4,5);

list.stream()
    .parallel()
    .forEach(System.out::print);

A. 12345
B. Ordered output always
C. Random order
D. Compile Error

✅ Answer: C

254. Which method is used to create a new thread using ExecutorService?

A. run()
B. submit()
C. start()
D. execute()

✅ Answer: D

255. Output?


String s1 = "Java";
String s2 = new String("Java").intern();

System.out.println(s1 == s2);

A. true
B. false
C. Compile Error
D. Runtime Error

✅ Answer: A

256. Which JVM memory area stores method definitions?

A. Heap
B. Stack
C. Method Area
D. PC Register

✅ Answer: C

257. Output?


System.out.println(Math.round(5.6));

A. 5
B. 6
C. 5.6
D. Error

✅ Answer: B

258. Which keyword prevents serialization of a variable?

A. static
B. final
C. transient
D. volatile

✅ Answer: C

259. Output?


List<Integer> list = Arrays.asList(1,2,3);

System.out.println(list.stream()
    .map(x -> x * x)
    .reduce(0, Integer::sum));

A. 6
B. 14
C. 9
D. 12

✅ Answer: B

260. Which interface allows comparison of two objects?

A. Comparable
B. Runnable
C. Serializable
D. Cloneable

✅ Answer: A

261. Output?


String s = "HelloWorld";

System.out.println(s.substring(5,10));

A. World
B. Hello
C. Wor
D. Error

✅ Answer: A

262. Which method returns current time in milliseconds?

A. System.nanoTime()
B. System.currentTime()
C. System.currentTimeMillis()
D. Date.now()

✅ Answer: C

263. Output?


AtomicInteger ai = new AtomicInteger(10);

System.out.println(ai.getAndIncrement());
System.out.println(ai.get());

A. 10 11
B. 11 11
C. 10 10
D. 11 12

✅ Answer: A

264. Which stream operation is terminal?

A. map()
B. filter()
C. sorted()
D. collect()

✅ Answer: D

265. Output?


List<String> list = Arrays.asList("a","b","c");

System.out.println(list.stream().count());

A. 2
B. 3
C. 4
D. Error

✅ Answer: B

266. Which keyword is used for object-level locking?

A. static
B. synchronized
C. volatile
D. transient

✅ Answer: B

267. Output?


System.out.println(Integer.parseInt("10") + 10);

A. 1010
B. 20
C. 10
D. Error

✅ Answer: B

268. Which class is immutable in Java?

A. StringBuilder
B. StringBuffer
C. String
D. ArrayList

✅ Answer: C

269. Output?


List<Integer> list = Arrays.asList(1,2,3,4);

System.out.println(list.stream()
    .filter(x -> x % 2 == 0)
    .count());

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

270. Which class is used for date-time in Java 8?

A. Date
B. Calendar
C. LocalDateTime
D. Timestamp

✅ Answer: C

271. Output?


String s = "Java";

System.out.println(s.repeat(3));

A. JavaJavaJava
B. Java3
C. 3Java
D. Error

✅ Answer: A

272. Which method is used to stop thread execution permanently (deprecated)?

A. stop()
B. destroy()
C. kill()
D. exit()

✅ Answer: A

273. Output?


List<Integer> list = Arrays.asList(5,10,15,20);

System.out.println(list.stream()
    .max(Integer::compareTo)
    .get());

A. 5
B. 10
C. 15
D. 20

✅ Answer: D

274. Which collection does NOT allow duplicates?

A. ArrayList
B. HashSet
C. LinkedList
D. Vector

✅ Answer: B

275. Output?


System.out.println(Optional.of("Java").isPresent());

A. true
B. false
C. null
D. Error

✅ Answer: A


System.out.println(s.hashCode());

A. Always same value
B. Random value
C. Error
D. Null

✅ Answer: A

300. Which feature allows multiple methods with same name but different parameters?

A. Overriding
B. Overloading
C. Encapsulation
D. Abstraction

✅ Answer: B

Java Expert Level MCQ Set-14 (301–325)

301. Which JVM feature prevents memory leaks automatically?

A. Class Loader
B. Garbage Collector
C. JIT Compiler
D. Interpreter

✅ Answer: B

302. Output?


System.out.println(10 + 20 + "Java" + 10 + 20);

A. 30Java1020
B. Java3010
C. 1020Java30
D. Java30

✅ Answer: A

303. Which method causes thread to pause temporarily?

A. wait()
B. sleep()
C. stop()
D. suspend()

✅ Answer: B

304. Output?


String s = "Java";
s.concat("8");
System.out.println(s);

A. Java8
B. 8Java
C. Java
D. Error

✅ Answer: C

305. Which class is used to prevent race condition?

A. Thread
B. Runnable
C. synchronized block
D. Executor

✅ Answer: C

306. Output?


System.out.println(1 + 2 + "3" + 4 + 5);

A. 12345
B. 3345
C. 334
D. 15

✅ Answer: B

307. Which collection allows null key?

A. TreeMap
B. HashMap
C. ConcurrentHashMap
D. Hashtable

✅ Answer: B

308. Output?


int x = 10;
System.out.println(x >>> 1);

A. 5
B. 10
C. 20
D. 0

✅ Answer: A

309. Which keyword prevents method override?

A. static
B. final
C. abstract
D. volatile

✅ Answer: B

310. Output?


String s = null;
System.out.println(s + "Java");

A. nullJava
B. Java
C. NullPointerException
D. Error

✅ Answer: A

311. Which interface is marker interface?

A. Runnable
B. Comparable
C. Serializable
D. Callable

✅ Answer: C

312. Output?


System.out.println(Math.abs(-10.5));

A. -10.5
B. 10.5
C. 10
D. Error

✅ Answer: B

313. Which collection is fastest for search by key?

A. ArrayList
B. LinkedList
C. HashMap
D. TreeSet

✅ Answer: C

314. Output?


List<Integer> list = Arrays.asList(1,2,3);

System.out.println(list.stream().count());

A. 1
B. 2
C. 3
D. 0

✅ Answer: C

315. Which JVM memory stores method code?

A. Heap
B. Stack
C. Method Area
D. PC Register

✅ Answer: C

316. Output?


String s1 = "Java";
String s2 = new String("Java");

System.out.println(s1 == s2);

A. true
B. false
C. Error
D. Exception

✅ Answer: B

317. Which class is used for thread pool?

A. Thread
B. ExecutorService
C. Runnable
D. Future

✅ Answer: B

318. Output?


System.out.println(5 << 2);

A. 10
B. 20
C. 25
D. 15

✅ Answer: B

319. Which method returns stream of collection?

A. getStream()
B. stream()
C. toStream()
D. createStream()

✅ Answer: B

320. Output?


System.out.println("Java".equalsIgnoreCase("JAVA"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

321. Which class handles file input/output?

A. Scanner
B. File
C. BufferedReader
D. Stream

✅ Answer: B

322. Output?


System.out.println(Math.min(100, 200));

A. 100
B. 200
C. 300
D. Error

✅ Answer: A

323. Which collection allows duplicate values but unique keys?

A. Set
B. List
C. Map
D. Queue

✅ Answer: C

324. Output?


String s = "Java";
System.out.println(s.replace('a','A'));

A. JAVa
B. JAvA
C. JAVA
D. Java

✅ Answer: B

325. Which keyword is used for exception handling?

A. throw
B. throws
C. try
D. all of the above

✅ Answer: D

Java Expert Level MCQ Set-15 (326–350)

326. What happens in deadlock situation?

A. Program runs faster
B. Threads wait forever
C. Memory increases
D. CPU usage becomes zero

✅ Answer: B

327. Output?


class A {
    static int x = 10;
    static {
        x = x + 5;
    }
}

public class Test {
    public static void main(String[] args) {
        System.out.println(A.x);
    }
}

A. 10
B. 15
C. 5
D. 0

✅ Answer: B

328. Which state is NOT a thread state in Java?

A. NEW
B. RUNNABLE
C. WAITING
D. EXECUTING

✅ Answer: D

329. Output?


System.out.println(10 * 0.1 == 1);

A. true
B. false
C. Compile Error
D. Exception

✅ Answer: B

330. Which class is used for reading characters efficiently?

A. File
B. BufferedReader
C. Scanner
D. StringReader

✅ Answer: B

331. Output?


String s = "Java";
System.out.println(s.substring(0, 0));

A. J
B. Java
C. ""
D. Error

✅ Answer: C

332. Which keyword is used to prevent serialization?

A. static
B. transient
C. final
D. volatile

✅ Answer: B

333. Output?


System.out.println(5 / 2 * 2);

A. 5
B. 4
C. 2
D. 6

✅ Answer: B

334. Which collection allows null elements multiple times?

A. HashSet
B. TreeSet
C. ArrayList
D. ConcurrentHashMap

✅ Answer: C

335. Output?


String s = "Java";
System.out.println(s.charAt(4));

A. a
B. v
C. Exception
D. null

✅ Answer: C

336. Which JVM component executes bytecode?

A. ClassLoader
B. GC
C. Interpreter
D. Compiler

✅ Answer: C

337. Output?


System.out.println(Integer.MAX_VALUE + 1);

A. Integer overflow value
B. Error
C. 0
D. Exception

✅ Answer: A

338. Which collection is best for LRU cache implementation?

A. ArrayList
B. HashMap
C. LinkedHashMap
D. TreeMap

✅ Answer: C

339. Output?


String s = "Java";
s = s.toUpperCase();
System.out.println(s);

A. Java
B. JAVA
C. java
D. Error

✅ Answer: B

340. Which keyword ensures thread safety of variable?

A. static
B. volatile
C. final
D. synchronized

✅ Answer: B

341. Output?


List<Integer> list = Arrays.asList(1,2,3,4);

System.out.println(
    list.stream().filter(x -> x > 2).count()
);

A. 1
B. 2
C. 3
D. 4

✅ Answer: B

342. Which method is used to stop thread execution safely?

A. stop()
B. interrupt()
C. destroy()
D. kill()

✅ Answer: B

Java Expert Level MCQ Set-16 (351–375)

351. Output?


int x = 0;
System.out.println(x++ + ++x + x++);

A. 1
B. 2
C. 3
D. 4

✅ Answer: C
Explanation:
x++ → 0 (x=1)
++x → 2 (x=2)
x++ → 2 (x=3)
Total = 0 + 2 + 2 = 4
⚠️ Correct answer is actually 4 (Option D)

352. Which collection is fail-fast?

A. CopyOnWriteArrayList
B. ArrayList
C. ConcurrentHashMap
D. CopyOnWriteArraySet

✅ Answer: B

353. Output?


System.out.println("Java".compareTo("Java"));

A. 1
B. -1
C. 0
D. Error

✅ Answer: C

354. Which class is thread-safe by default?

A. StringBuilder
B. StringBuffer
C. ArrayList
D. HashMap

✅ Answer: B

355. Output?


System.out.println(10 + 20 + "30" + 40 + 50);

A. 30304050
B. 303090
C. 1020304050
D. 303050

✅ Answer: A

356. Which method is used to convert stream to list?

A. collect(Collectors.toList())
B. toList() only
C. convert()
D. list()

✅ Answer: A

357. Output?


String s = null;
System.out.println(s + "Java");

A. Java
B. nullJava
C. Exception
D. Error

✅ Answer: B

358. Which JVM memory stores class metadata?

A. Heap
B. Stack
C. Method Area
D. PC Register

✅ Answer: C

359. Output?


System.out.println(Math.floor(9.9));

A. 9.0
B. 10.0
C. 9
D. Error

✅ Answer: A

360. Which interface allows sorting custom objects?

A. Runnable
B. Comparable
C. Cloneable
D. Serializable

✅ Answer: B

361. Output?


List<Integer> list = Arrays.asList(1,2,3);

System.out.println(list.stream().map(x -> x*x).count());

A. 1
B. 2
C. 3
D. 6

✅ Answer: C

362. Which class is immutable?

A. String
B. StringBuilder
C. StringBuffer
D. ArrayList

✅ Answer: A

363. Output?


System.out.println("Java".replace('a','A'));

A. JAVa
B. JAvA
C. JAVA
D. Java

✅ Answer: B

364. Which collection is best for priority-based ordering?

A. HashSet
B. TreeSet
C. PriorityQueue
D. ArrayList

✅ Answer: C

365. Output?


System.out.println(5 << 1);

A. 5
B. 10
C. 15
D. 20

✅ Answer: B

366. Which keyword prevents inheritance?

A. static
B. final
C. abstract
D. volatile

✅ Answer: B

367. Output?


System.out.println("Java".substring(1,3));

A. Ja
B. av
C. va
D. Jav

✅ Answer: B

368. Which collection allows duplicate keys?

A. HashMap
B. TreeMap
C. Hashtable
D. None

✅ Answer: D

369. Output?


System.out.println(Integer.parseInt("100") + 1);

A. 1001
B. 101
C. 100
D. Error

✅ Answer: B

370. Which Stream operation is intermediate?

A. collect()
B. reduce()
C. filter()
D. forEach()

✅ Answer: C

371. Output?


System.out.println("Java".equalsIgnoreCase("JAVA"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

372. Which class is used for reading input?

A. System
B. Scanner
C. Input
D. ReaderManager

✅ Answer: B

373. Output?


System.out.println(Math.max(100, 99));

A. 99
B. 100
C. 199
D. Error

✅ Answer: B

374. Which collection maintains insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

375. Output?


List<Integer> list = Arrays.asList(2,4,6);

System.out.println(list.stream().allMatch(x -> x % 2 == 0));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

Java Expert Level MCQ Set-17 (376–400)

376. What is a livelock?

A. Threads are blocked forever
B. Threads keep responding but no progress
C. CPU stops working
D. Memory overflow

✅ Answer: B

377. Output?


String s1 = "Java";
String s2 = "Ja" + "va";

System.out.println(s1 == s2);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

378. Which JVM component loads .class files?

A. JIT Compiler
B. Garbage Collector
C. ClassLoader
D. Interpreter

✅ Answer: C

379. Output?


System.out.println(10 / 0.0);

A. Infinity
B. NaN
C. Exception
D. 0

✅ Answer: A

380. Which collection is NOT thread-safe?

A. Vector
B. Hashtable
C. ArrayList
D. ConcurrentHashMap

✅ Answer: C

381. Output?


System.out.println(Float.NaN == Float.NaN);

A. true
B. false
C. Error
D. Exception

✅ Answer: B

382. Which method is used to check thread state?

A. getStatus()
B. getState()
C. state()
D. checkState()

✅ Answer: B

383. Output?


int x = 5;
System.out.println(x > 5 ? 10 : 20);

A. 5
B. 10
C. 20
D. Error

✅ Answer: C

384. Which class is used for high-performance logging?

A. System.out
B. Logger
C. PrintStream
D. FileWriter

✅ Answer: B

385. Output?


String s = "Java";
System.out.println(s + null);

A. Java
B. null
C. Javanull
D. Error

✅ Answer: C

386. Which keyword is used for runtime exception handling?

A. throws
B. try
C. catch
D. all of the above

✅ Answer: D

387. Output?


System.out.println(Math.sqrt(-1));

A. -1
B. NaN
C. Exception
D. Error

✅ Answer: B

388. Which memory area stores method calls?

A. Heap
B. Stack
C. Method Area
D. GC Heap

✅ Answer: B

389. Output?


String s = "Java";
System.out.println(s.length());

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

390. Which collection allows duplicate elements and maintains order?

A. HashSet
B. TreeSet
C. ArrayList
D. HashMap

✅ Answer: C

391. Output?


System.out.println(5 + 10 + "20" + 30);

A. 152030
B. 1520
C. 202530
D. Error

✅ Answer: A

392. Which interface is used for custom sorting?

A. Comparable
B. Runnable
C. Serializable
D. Cloneable

✅ Answer: A

393. Output?


System.out.println("Java".substring(2));

A. Ja
B. av
C. va
D. Java

✅ Answer: C

394. Which collection stores unique sorted elements?

A. HashSet
B. LinkedHashSet
C. TreeSet
D. ArrayList

✅ Answer: C

395. Output?


System.out.println(2 << 3);

A. 8
B. 16
C. 10
D. 24

✅ Answer: B

396. Which keyword prevents method overriding?

A. static
B. final
C. abstract
D. transient

✅ Answer: B

397. Output?


System.out.println("Java".indexOf('a'));

A. 0
B. 1
C. 2
D. 3

✅ Answer: B

398. Which class is used for file reading?

A. File
B. BufferedReader
C. Scanner
D. All of the above

✅ Answer: D

399. Output?


System.out.println(Math.abs(-100));

A. -100
B. 100
C. 0
D. Error

✅ Answer: B

400. Which Stream method is terminal?

A. map()
B. filter()
C. collect()
D. sorted()

✅ Answer: C

Java Expert Level MCQ Set-18 (401–425)

401. What is a memory leak in Java?

A. Stack overflow
B. Objects not garbage collected due to references
C. CPU overload
D. Thread blocking

✅ Answer: B

402. Output?


System.out.println("Java".charAt(4));

A. a
B. v
C. Exception
D. null

✅ Answer: C

403. Which GC is designed for low latency?

A. Serial GC
B. G1 GC
C. ZGC
D. Parallel GC

✅ Answer: C

404. Output?


System.out.println(1.0 / 0);

A. Infinity
B. NaN
C. Exception
D. 0

✅ Answer: A

405. Which class is immutable?

A. StringBuilder
B. StringBuffer
C. String
D. ArrayList

✅ Answer: C

406. Output?


int x = Integer.MAX_VALUE;
System.out.println(x + 1);

A. Integer.MIN_VALUE
B. Overflow garbage
C. Error
D. 0

✅ Answer: A

407. Which interface supports parallel execution?

A. Runnable
B. Stream
C. ExecutorService
D. ForkJoinPool

✅ Answer: D

408. Output?


System.out.println("Java" + 10 + 20);

A. Java30
B. Java1020
C. 30Java
D. Error

✅ Answer: B

409. Which keyword ensures visibility across threads?

A. static
B. volatile
C. final
D. transient

✅ Answer: B

410. Output?


String s = null;
System.out.println(s.length());

A. null
B. 0
C. Exception
D. Error

✅ Answer: C

411. Which class is used for high-performance concurrent queue?

A. ArrayList
B. LinkedList
C. ConcurrentLinkedQueue
D. HashSet

✅ Answer: C

412. Output?


System.out.println(Math.round(5.4));

A. 5
B. 6
C. 5.0
D. Error

✅ Answer: A

413. Which method starts a thread?

A. run()
B. start()
C. execute()
D. begin()

✅ Answer: B

414. Output?


System.out.println("Java".equalsIgnoreCase("JAVA"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

415. Which memory area stores local variables?

A. Heap
B. Method Area
C. Stack
D. GC Area

✅ Answer: C

416. Output?


System.out.println(10 >> 2);

A. 2
B. 5
C. 8
D. 10

✅ Answer: A

417. Which collection allows duplicate keys?

A. HashMap
B. TreeMap
C. Hashtable
D. None

✅ Answer: D

418. Output?


System.out.println("Java".substring(1,3));

A. Ja
B. av
C. va
D. Jav

✅ Answer: B

419. Which Stream operation is terminal?

A. map()
B. filter()
C. collect()
D. sorted()

✅ Answer: C

420. Output?


List<Integer> list = Arrays.asList(1,2,3);

System.out.println(list.stream().count());

A. 1
B. 2
C. 3
D. Error

✅ Answer: C

421. Which exception is unchecked?

A. IOException
B. SQLException
C. NullPointerException
D. InterruptedException

✅ Answer: C

422. Output?


System.out.println(Math.max(10,20));

A. 10
B. 20
C. 30
D. Error

✅ Answer: B

423. Which collection preserves insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

424. Output?


System.out.println(5 * 2 + 3);

A. 13
B. 16
C. 10
D. 15

✅ Answer: A

425. Which class is used for reading user input?

A. System
B. Scanner
C. InputReader
D. Buffer

✅ Answer: B

Java Expert Level MCQ Set-19 (426–450)

426. What is a deadlock condition?

A. One thread finishes early
B. Threads wait forever for each other’s lock
C. CPU becomes faster
D. Memory is freed

✅ Answer: B

427. Output?


System.out.println(0.0 / 0.0);

A. 0
B. NaN
C. Infinity
D. Exception

✅ Answer: B

428. Which JVM component converts bytecode to native code at runtime?

A. ClassLoader
B. JIT Compiler
C. GC
D. Interpreter

✅ Answer: B

429. Output?


String s = "Java";
System.out.println(s.substring(2,2));

A. va
B. v
C. ""
D. Error

✅ Answer: C

430. Which collection is best for LRU cache?

A. HashMap
B. TreeMap
C. LinkedHashMap
D. HashSet

✅ Answer: C

431. Output?


System.out.println("Java".replace("a", "A"));

A. JAVa
B. JAvA
C. JAVA
D. Java

✅ Answer: B

432. Which interface is used for lambda expressions?

A. Serializable
B. Functional Interface
C. Marker Interface
D. Cloneable

✅ Answer: B

433. Output?


System.out.println(10 + 20 + "Java" + 30);

A. 30Java30
B. Java3030
C. 1020Java30
D. Java102030

✅ Answer: A

434. Which memory area stores method calls?

A. Heap
B. Stack
C. Method Area
D. GC Heap

✅ Answer: B

435. Output?


System.out.println(Integer.parseInt("010"));

A. 10
B. 8
C. 1
D. Error

✅ Answer: A

436. Which class provides thread pool management?

A. Thread
B. ExecutorService
C. Runnable
D. Future

✅ Answer: B

437. Output?


List<Integer> list = Arrays.asList(1,2,3);

System.out.println(list.stream().map(x -> x * 2).count());

A. 2
B. 3
C. 6
D. Error

✅ Answer: B

438. Which keyword prevents inheritance?

A. static
B. final
C. volatile
D. abstract

✅ Answer: B

439. Output?


System.out.println("Java".indexOf("a"));

A. 0
B. 1
C. 2
D. 3

✅ Answer: B

440. Which collection allows null key?

A. TreeMap
B. HashMap
C. ConcurrentHashMap
D. Hashtable

✅ Answer: B

441. Output?


System.out.println(5 >> 1);

A. 2
B. 3
C. 5
D. 10

✅ Answer: A

442. Which method is used to create stream from collection?

A. stream()
B. toStream()
C. createStream()
D. getStream()

✅ Answer: A

443. Output?


System.out.println("Java".equals("java"));

A. true
B. false
C. Error
D. Exception

✅ Answer: B

444. Which class is immutable?

A. StringBuilder
B. StringBuffer
C. String
D. ArrayList

✅ Answer: C

445. Output?


System.out.println(Math.abs(-50));

A. -50
B. 50
C. 0
D. Error

✅ Answer: B

446. Which Stream operation is terminal?

A. map()
B. filter()
C. sorted()
D. forEach()

✅ Answer: D

447. Output?


System.out.println(2 << 2);

A. 4
B. 6
C. 8
D. 10

✅ Answer: C

448. Which class is used for file handling?

A. Scanner
B. File
C. InputStream
D. Reader

✅ Answer: B

449. Output?


System.out.println("Java".length());

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

450. Which collection does NOT allow duplicates?

A. ArrayList
B. HashSet
C. LinkedList
D. Vector

✅ Answer: B

Java Expert Level MCQ Set-20 (451–475) 🚀

451. What is starvation in multithreading?

A. Thread completes too fast
B. Thread never gets CPU time
C. Memory leak
D. Deadlock recovery

✅ Answer: B

452. Output?


System.out.println(10 + 20 + "Java" + 10 * 2);

A. 30Java20
B. 1020Java20
C. Java3020
D. 30Java1020

✅ Answer: A

453. Which GC is best for large heap & low pause time?

A. Serial GC
B. Parallel GC
C. G1 GC
D. Mark Sweep GC

✅ Answer: C

454. Output?


String s = "Java";
System.out.println(s.substring(1));

A. J
B. Java
C. ava
D. av

✅ Answer: C

455. Which class is used for atomic operations?

A. Integer
B. AtomicInteger
C. Number
D. Math

✅ Answer: B

456. Output?


System.out.println(Float.NaN != Float.NaN);

A. true
B. false
C. Error
D. Exception

✅ Answer: A

457. Which interface supports functional programming?

A. Runnable
B. Functional Interface
C. Serializable
D. Cloneable

✅ Answer: B

458. Output?


System.out.println("Java".charAt(1));

A. J
B. a
C. v
D. Error

✅ Answer: B

459. Which memory area stores objects?

A. Stack
B. Heap
C. Method Area
D. PC Register

✅ Answer: B

460. Output?


System.out.println(5 / 2);

A. 2.5
B. 2
C. 3
D. Error

✅ Answer: B

461. Which collection is thread-safe?

A. ArrayList
B. HashMap
C. Vector
D. LinkedList

✅ Answer: C

462. Output?


System.out.println("Java" + null);

A. null
B. Java
C. Javanull
D. Error

✅ Answer: C

463. Which method starts thread execution?

A. run()
B. start()
C. execute()
D. begin()

✅ Answer: B

464. Output?


System.out.println(Math.pow(2,3));

A. 6
B. 8
C. 9
D. Error

✅ Answer: B

465. Which collection maintains sorted order?

A. HashSet
B. TreeSet
C. ArrayList
D. LinkedList

✅ Answer: B

466. Output?


System.out.println("Java".equalsIgnoreCase("JAVA"));

A. true
B. false
C. Error
D. Exception

✅ Answer: A

467. Which keyword is used for inheritance?

A. this
B. super
C. extends
D. implements

✅ Answer: C

468. Output?


System.out.println(10 >> 1);

A. 5
B. 10
C. 20
D. 2

✅ Answer: A

469. Which Stream method is terminal?

A. map()
B. filter()
C. collect()
D. sorted()

✅ Answer: C

470. Output?


System.out.println("Java".replace("a","A"));

A. JAVa
B. JAvA
C. JAVA
D. Java

✅ Answer: B

471. Which class is immutable?

A. StringBuffer
B. StringBuilder
C. String
D. ArrayList

✅ Answer: C

472. Output?


System.out.println(Math.min(100, 200));

A. 100
B. 200
C. 300
D. Error

✅ Answer: A

473. Which collection allows duplicates?

A. Set
B. Map
C. List
D. TreeSet

✅ Answer: C

474. Output?


System.out.println("Java".indexOf('v'));

A. 1
B. 2
C. 3
D. -1

✅ Answer: B

475. Which keyword prevents method override?

A. static
B. final
C. abstract
D. volatile

✅ Answer: B

🔥 Java Expert Level MCQ Set-21 (476–500) — FINAL BOSS ROUND

476. Which JVM phase loads classes?

A. Execution Engine
B. Class Loading
C. Garbage Collection
D. Compilation

✅ Answer: B

477. Output?


System.out.println("Java" == "Ja" + "va");

A. true
B. false
C. Error
D. Exception

✅ Answer: A

478. Which GC reduces pause time most?

A. Serial GC
B. Parallel GC
C. G1 GC
D. CMS GC (legacy)

✅ Answer: C

479. Output?


System.out.println(10 / 0);

A. Infinity
B. 0
C. Exception
D. NaN

✅ Answer: C

480. Which class is used for thread pooling?

A. Thread
B. ExecutorService
C. Runnable
D. Callable

✅ Answer: B

481. Output?


String s = null;
System.out.println(s);

A. null
B. Exception
C. Error
D. 0

✅ Answer: A

482. Which method causes deadlock risk?

A. notify()
B. synchronized blocks
C. sleep()
D. yield()

✅ Answer: B

483. Output?


System.out.println(1 + 2 + "3" + 4 + 5);

A. 12345
B. 3345
C. 334
D. 15

✅ Answer: B

484. Which memory area is garbage collected?

A. Stack
B. Heap
C. Method Area
D. PC Register

✅ Answer: B

485. Output?


System.out.println(Math.sqrt(16));

A. 8
B. 4
C. 16
D. Error

✅ Answer: B

486. Which interface is functional?

A. Runnable
B. Comparable
C. Both A and B
D. None

✅ Answer: C

487. Output?


String s = "Java";
System.out.println(s.repeat(2));

A. Java
B. JavaJava
C. 2Java
D. Error

✅ Answer: B

488. Which keyword ensures thread visibility?

A. static
B. volatile
C. final
D. transient

✅ Answer: B

489. Output?


System.out.println("Java".substring(1,4));

A. Jav
B. ava
C. va
D. a

✅ Answer: B

490. Which collection is fastest for lookup?

A. ArrayList
B. LinkedList
C. HashMap
D. TreeMap

✅ Answer: C

491. Output?


System.out.println(5 << 1);

A. 5
B. 10
C. 15
D. 20

✅ Answer: B

492. Which class prevents multiple inheritance?

A. final
B. abstract
C. interface
D. object

✅ Answer: A

493. Output?


System.out.println("Java".equals("JAVA"));

A. true
B. false
C. Error
D. Exception

✅ Answer: B

494. Which Stream operation returns single value?

A. map()
B. filter()
C. reduce()
D. sorted()

✅ Answer: C

495. Output?


System.out.println("Java".indexOf("a"));

A. 0
B. 1
C. 2
D. 3

✅ Answer: B

496. Which collection preserves insertion order?

A. HashSet
B. TreeSet
C. LinkedHashSet
D. PriorityQueue

✅ Answer: C

497. Output?


System.out.println(Math.abs(-999));

A. -999
B. 999
C. 0
D. Error

✅ Answer: B

498. Which keyword prevents method override?

A. static
B. final
C. abstract
D. volatile

✅ Answer: B

499. Output?


System.out.println("Java".length());

A. 3
B. 4
C. 5
D. Error

✅ Answer: B

500. 🎯 FINAL QUESTION (HARD)


String s1 = "Java";
String s2 = new String("Java").intern();
String s3 = "Ja" + "va";

System.out.println(s1 == s2);
System.out.println(s1 == s3);
System.out.println(s2 == s3);

A.
true true true

B.
false false false

C.
true true false

D.
false true false

✅ Correct Answer: C

Explanation:

intern() → string pool reference
"Ja" + "va" → compile-time constant → pool
All point to same pooled object

So:


true
true
false

🏆 FINAL RESULT

🎉 You have completed:

Java Hard Level MCQ Set-1 (1-10) Total = 500

1. What is the Output?

2. Which collection maintains insertion order?

3. Which keyword prevents inheritance?

4. What is the output?

5. Which exception is unchecked?

6. What is the default value of boolean?

7. Which interface is implemented by ArrayList?

8. Output?

9. Which Java feature supports runtime polymorphism?

10. Which package contains Scanner?

Java Hard Level MCQ Set-2 (11-20)

11. Output?

12. Which class is immutable?

13. Which collection allows duplicate elements?

14. What is JVM?

15. Which access modifier gives maximum accessibility?

16. Output?

17. Which class cannot be instantiated?

18. Which collection sorts elements automatically?

19. Which keyword is used for inheritance?

20. Which method starts a thread?

Hard Coding MCQ Example

21. Output?

22. Output?

23. Output?

24. Output?

25. Which class is thread-safe?

Java Hard Level MCQ Set-3 (26–50)

26. Output?

27. Output?

28. Which collection does NOT allow duplicate keys?

29. Output?

30. Which keyword refers to parent class constructor?

31. Output?

32. Which class is used for dynamic string modification?

33. Output?

34. Which interface supports lambda expressions?

35. Output?

36. Output?

37. Which exception occurs when dividing by zero?

38. Output?

39. Which collection stores key-value pairs?

40. Output?

41. Which keyword is used to create a constant?

42. Output?

43. Which collection is synchronized by default?

44. Output?

45. Which method is called automatically by garbage collector?

46. Output?

47. Which Java feature hides implementation details?

48. Output?

49. Which collection provides FIFO behavior?

50. Output?

Java Hard Level MCQ Set-4 (51–75)

51. Output?

52. Which collection allows one null key?

53. Output?

54. Which keyword is used to inherit an interface?

55. Output?

56. Which class is NOT part of Collection Framework?

57. Output?

58. Which Java 8 feature enables functional programming?

59. Output?

60. Which collection sorts keys?

61. Output?

62. Which exception occurs when a string is converted to an invalid number?

63. Output?

64. Which keyword prevents method overriding?

65. Output?

66. Which collection is best for unique sorted elements?

67. Output?

68. Which package contains Stream API?

69. Output?

70. Which interface is used for sorting custom objects?

71. Output?

72. Which method removes leading and trailing spaces?

73. Output?

74. Which class is used to read user input?

75. Output?