What will this code output? int result = 0; try { result = 10 / 0; } catch(Exception e) { result = 20; return result; } finally { result = 30; } System.out.println(result);

The correct answer is A: 20. Return statement in catch block prepares the return value (20). Finally block executes but return happens after finally, so 20 is returned even though finally sets result to 30.

Given: Map map = new HashMap(); map.put("A", 10); map.put("B", 20); map.put("A", 30); What will be the size of map?

The correct answer is B: 2. HashMap stores unique keys. Putting same key 'A' again replaces the old value. Size remains 2 with keys A and B.

Which of the following will compile without error? public static void main(String args[]) { int x = 10; final int y = 20; y = 30; }

The correct answer is B: No, compilation error on y = 30. Once a final variable is assigned, it cannot be reassigned. The line 'y = 30;' will cause a compilation error.

Which of the following is NOT a subclass of Throwable in Java?

The correct answer is D: Runnable. Runnable is a functional interface, not related to exception hierarchy. Error and Exception are direct subclasses of Throwable. RuntimeException is a subclass of Exception.

What is the serialVersionUID used for in Java serialization?

The correct answer is B: To identify the class version for deserialization compatibility. serialVersionUID identifies class versions. Mismatched versions cause InvalidClassException during deserialization.

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Java Programming

Java OOP, collections, multithreading

476 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 451–460 of 476

Topics in Java Programming

All Basics & Syntax 100 OOP in Java 100 Collections Framework 100 Multithreading 100 Exception Handling 100 I/O Streams 100 JDBC 100 Generics 100 Lambda Expressions 100 Spring Framework Basics 58

Q.451 Medium Basics & Syntax

Which of the following cannot be inherited in Java?

A Public methods

B Protected methods

C Private methods

D Static methods can be inherited

Correct Answer: C. Private methods

EXPLANATION

Private members are not inherited. They remain accessible only within the class they are declared in.

Test

Q.452 Medium Basics & Syntax

Which of the following about static variables is incorrect?

A Static variables are shared among all instances

B Static variables are initialized when class loads

C Each object has its own copy of static variables

D Static variables can be accessed using class name

Correct Answer: C. Each object has its own copy of static variables

EXPLANATION

Static variables are shared among ALL instances of a class, not individual copies per object.

Test

Q.453 Medium Basics & Syntax

What is the output of: System.out.println(5 % 2 + 3 * 2 - 1);?

A 6

B 7

C 8

D 10

Correct Answer: A. 6

EXPLANATION

Following operator precedence: 5%2=1, 3*2=6, then 1+6-1=6

Test

Q.454 Medium Basics & Syntax

Which statement about constructor overloading is true?

A Constructors cannot be overloaded

B Constructors can be overloaded with different parameter types and counts

C Only one constructor is allowed per class

D Constructor return type must differ for overloading

Correct Answer: B. Constructors can be overloaded with different parameter types and counts

EXPLANATION

Constructors can be overloaded based on parameter count and types, but not on return type.

Test

Q.455 Medium Basics & Syntax

Which access modifier allows access within the same package and subclasses?

A public

B private

C protected

D default

Correct Answer: C. protected

EXPLANATION

protected allows access within the same package and to subclasses even outside the package.

Test

Q.456 Medium Basics & Syntax

What is the difference between == and .equals() for String comparison?

A Both check string content

B == checks reference, .equals() checks content

C == checks content, .equals() checks reference

D They are identical in functionality

Correct Answer: B. == checks reference, .equals() checks content

EXPLANATION

== compares object references (memory location), while .equals() compares the actual string content.

Test

Q.457 Medium Basics & Syntax

Which statement about Java's 'this' keyword is correct?

A 'this' refers to the parent class

B 'this' refers to the current object instance

C 'this' is a static reference

D 'this' cannot be used in constructors

Correct Answer: B. 'this' refers to the current object instance

EXPLANATION

'this' is a reference to the current object instance. It's used to distinguish instance variables from parameters and to call other constructors.

Test

Q.458 Medium Basics & Syntax

What is the output of: double d = 5.7; int i = (int) d; System.out.println(i);

A 6

B 5.7

C 5

D Error

Correct Answer: C. 5

EXPLANATION

Explicit casting from double to int truncates the decimal part. 5.7 becomes 5 (not rounded).

Test

Q.459 Medium Basics & Syntax

What will be the output: int a = 10; int b = 20; System.out.println(a > b ? "A" : "B");

A A

B B

C Error

D AB

Correct Answer: B. B

EXPLANATION

Ternary operator: condition ? trueValue : falseValue. Since 10 > 20 is false, "B" is printed.

Test

Q.460 Medium Basics & Syntax

Which of the following correctly initializes a 2D array in Java?

A int[][] arr = new int[3][4];

B int[] arr[] = new int[3][4];

C Both A and B

D Neither A nor B

Correct Answer: C. Both A and B

EXPLANATION

Both syntaxes are valid in Java for declaring 2D arrays. The brackets can be placed after the type or variable name.

Test

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