Think you're a Java expert? Test your knowledge of the Java programming language, from syntax and libraries to best practices and design patterns. See how much of a Java guru you really are!
1. What does JVM stand for in Java?
Java Verified Machine
Java Value Machine
Java Virtual Memory
Java Virtual Machine
2. What is the primary benefit of using the 'StringBuilder' class in Java over the 'String' class?
StringBuilder is immutable
StringBuilder offers better memory sharing
StringBuilder reduces memory overhead with append operations
StringBuilder is more secure for multithreaded operations
3. What is the primary purpose of the Java garbage collector?
To free up memory by removing objects that are no longer in use
To compile source code
To manage CPU usage
To manually handle all memory allocations
4. Which keyword is used to define a class in Java?
className
structure
class
object
5. What is the default value of a boolean in Java?
0
false
true
null
6. Which of the following is used for thread synchronization in Java?
volatile
transient
abstract
synchronized
7. Which method must be implemented by all threads in Java?
run()
start()
main()
execute()
8. What is an interface in Java?
A reference type in Java that is similar to a class and is a collection of abstract methods
An instance variable
A class method
A data structure
9. What does the 'extends' keyword in Java indicate?
To declare a constant
To indicate that a class is inheriting from another class
To create an instance of a class
To implement an interface
10. How would you describe encapsulation in Java?
The wrapping of data and methods into a single unit
The use of base and derived classes
Inheritance used to derive new classes from existing ones
The ability of multiple methods to perform different functions
11. What is the function of the 'final' keyword in Java?
It is used to declare constants, prevent inheritance, and prevent method overriding
To define a class
To create new instances of a class
To indicate a null value
12. Which type of variable is shared among all instances of a class?
Instance variable
Local variable
Abstract variable
Static variable
13. How do you handle exceptions in Java?
Using goto statements
Using try-catch-finally blocks
Using printf statements
Using error codes
14. What is polymorphism in Java?
The ability of different objects to respond in a unique way to the same method call
Creating a new class from an existing class
The process of defining multiple methods with the same name
The wrapping of data and methods into a single unit
15. What is the purpose of the keyword 'transient' in Java?
