Advanced Java MCQs with Answers to Practice.

In the ever-evolving world of development, learning never stops. Java, a critical programming language, continues to advance, making it essential for developers to stay updated with its latest developments.

With growing demands for new features, Java developers continually learn to apply their knowledge to their ongoing projects. This helps them to stay current and updated. However, while they learn on the go, it’s equally important for them to test their knowledge.

This collection of advanced Java multiple-choice questions (MCQs) is designed to help developers deepen their understanding and do self-assessments. With the help of these questions, they can challenge their learnings and expand their knowledge.

The topics covered in these advanced Java MCQs include Type Checking, Abstract Classes, Static Members, Assertions, Enumerations, Boxing, Garbage Collection, and so on. 

So, let’s dive straight into these Advanced Java MCQs with answers and test your knowledge.

Advanced Java MCQs with Answers

Here's a set of MCQs designed to test and improve your advanced Java knowledge: 

Q1. What does the 'transient' keyword do in Java?

1. Prevents a variable from being serialized.
2. Restricts access to a variable outside its Class.
3. Denotes a variable as immutable.
4. Marks a variable as constant.

Answer: A. Prevents a variable from being serialized.

Q2. Why use the 'volatile' keyword in Java?

1. Ensures a variable's value never changes.
2. Guarantees single-threaded access to a variable.
3. Signals that a variable's value may change unexpectedly.
4. Forces simultaneous access to a variable by multiple threads.

Answer: C. Signals that a variable's value may change unexpectedly.

Q3. When does the 'finally' block execute in Java?

1. Only if an exception occurs.
2. Only if no exception occurs.
3. Regardless of whether an exception occurs or not.
4. It's not a valid construct in Java.

Answer: C. Regardless of whether an exception occurs or not.

Q4. What is the function of the super keyword in Java?

1. Access variables and methods of the current Class.
2. Invoke the superclass constructor.
3. Indicate a class cannot be inherited.
4. Define a superclass.

Answer: B. Invoke the superclass constructor.

Q5. What does the 'static' keyword signify in Java?

1. Indicates that a variable is constant.
2. Denotes a method or variable belonging to the Class rather than instances.
3. Specifies a method that cannot be overridden.
4. Signals a variable that can be accessed only within its class.

Answer: B. Denotes a method or variable belonging to the Class rather than instances.

Q6. Which of the following is true for Java's abstract classes?

1. They cannot have constructors.
2. They must implement all methods declared abstract.
3. They can be instantiated.
4. They are used to create objects directly.

Answer: A. They cannot have constructors.

Q7. What is the function of the 'this' keyword in Java?

1. Access variables and methods of the current Class.
2. Invoke the superclass constructor.
3. Indicate a class cannot be inherited.
4. Define a subclass.

Answer: A. Access variables and methods of the current Class.

Q8. What role does the 'extends' keyword play in Java?

1. Implements an interface.
2. Indicates that a class inherits from another class.
3. Defines a superclass.
4. Denotes a method is overloaded.

Answer: B. Indicates that a class inherits from another class.

Q9. What is the purpose of the 'new' keyword in Java?

1. Allocates memory for a new object or array.
2. Marks a class as new and experimental.
3. Creates a constant value.
4. Initializes a variable with a default value.

Answer: A. Allocates memory for a new object or array.

Q10. What does the 'final' keyword signify in Java?

1. Indicates that a variable's value cannot be changed.
2. Denotes a method that cannot be overridden.
3. Specifies a class that cannot be subclassed.
4. Signals a variable that can be accessed only within its class.

Answer: A. Indicates that a variable's value cannot be changed.

Q11. Why is the 'instance of' operator used in Java?

1. Checks if an object is null.
2. Determines if an object is of a particular type.
3. Converts an object to a specified type.
4. Check if two objects are equal.

Answer: B. Determines if an object is of a particular type.

Q12. What is the Java "break" statement used for?

1.  Exits a loop or switch statement.
2.  Continues to the next iteration of a loop.
3.  Throws an exception.
4.  Terminates the program.

Answer: A. Exits a loop or switch statement.

Q13. What is the purpose of the 'default' keyword in a switch statement in Java?

1. Specifies the default value for a variable.
2. Marks a class as the default access level.
3. Defines the default case in a switch statement.
4. Indicates the default behavior for a method.

Answer: C. Defines the default case in a switch statement.

Q14. What does the 'implements' keyword do in Java?

1. Declares a variable.
2. Indicates a class implements an interface.
3. Specifies a method's implementation.
4. Denotes a method is overloaded.

Answer: B. Indicates a class implements an interface.

Q15. What is the purpose of the 'static' keyword in Java?

1. Marks a method as private.
2. Indicates a variable is constant.
3. Allows access to a method or variable without an instance of the Class.
4. Prevents inheritance of a method or variable.

Answer: C. Allows access to a method or variable without an instance of the Class.

Q16. What is a lambda expression in Java primarily used for?

1. Defining anonymous classes.
2. Implementing functional interfaces concisely.
3. Enforcing encapsulation.
4. Overriding superclass methods.

Answer: B. Implementing functional interfaces concisely.

Q17. In Java, what does the 'assert' keyword signify?

1. Indicates a method as abstract.
2. Signals that a method will throw an exception.
3. Denotes a condition that should be true.
4. Marks a method as final.

Answer: C. Denotes a condition that should be true.

Q18. What does the 'this' keyword refer to in Java?

1. Refers to the current instance of the Class.
2. Refers to the superclass instance.
3. Refers to the subclass instance.
4. Refers to the global instance of the Class.

Answer: A. Refers to the current instance of the Class.

Q19. What is the purpose of the 'throws' clause in Java method declaration?

1. Specifies the superclass of an exception.
2. Indicates that a method may throw a specific type of exception.
3. Specify the parameters a method can accept.
4. Indicates that a method is abstract.

Answer: D. Indicates that a method may throw a specific type of exception.

Q20. Which Java feature allows a subclass to provide a particular implementation of a function that already exists in its superclass?

1. Overloading
2. Overriding
3. Inheritance
4. Polymorphism

Answer: B. Overriding

Q21. What is the main purpose of the synchronized keyword in Java?

1. Prevents a method from being overridden.
2. Ensures only one instance of a class is created.
3. Facilitates concurrent access to shared resources by multiple threads.
4. Marks a method as abstract.

Answer: C. Facilitates concurrent access to shared resources by multiple threads.

Q22. In Java, what is the primary function of the 'enum' keyword?

1. Marks a class as serializable.
2. Denotes a variable as immutable.
3. Defines a group of constants.
4. Indicates a method as synchronized.

Answer: C. Defines a group of constants.

Q23. What is the purpose of the 'finalize()' method in Java?

1. Cleans up system resources before an object is garbage collected.
2. Marks a method as deprecated.
3. Signals at the end of a program's execution.
4. Throws an exception when a condition is not met.

Answer: A. Cleans up system resources before an object is garbage collected.

Q24. What does the term "boxing" refer to in Java?

1. Converting a primitive type to its corresponding wrapper class object.
2. Enclosing code within a block.
3. Creating a deep copy of an object.
4. Executing multiple threads simultaneously.

Answer: A. Converting a primitive type to its corresponding wrapper class object.

Q25. What does the 'default' keyword signify in a Java interface?

1. Marks a method as private.
2. Indicates that a method has a default implementation.
3. Denotes a method as final.
4. Prevents a method from being overridden.

Answer: B. Indicates that a method has a default implementation.

Q26. In Java, what does the 'strictfp' keyword ensure?

1. Guarantees that a method is synchronized.
2. Specifies that floating-point calculations follow the IEEE 754 standard.
3. Prevents a method from being inherited.
4. Indicates that a method is abstract.

Answer: B. Specifies that floating-point calculations follow the IEEE 754 standard.

Q27. What is the primary function of the 'super()' method in Java?

1. Calls the superclass constructor.
2. Invokes a static method from the superclass.
3. Indicates that a method is synchronized.
4. Allows access to a superclass variable.

Answer: A. Calls the superclass constructor.

Q28. What is the purpose of the 'strictfp' keyword in Java?

1. Indicates that a class cannot be inherited.
2. Specifies that floating-point calculations follow the IEEE 754 standard.
3. Ensures that a method is synchronized.
4. Marks a method as abstract.

Answer: B. Specifies that floating-point calculations follow the IEEE 754 standard.

Q29. What is the significance of the 'instance of' operator in Java?

1. Determines if two objects are equal.
2. Check if an object is an instance of a particular class.
3. Compares the memory addresses of two objects.
4. Check if a class is a subclass of another class.

Answer: B. Check if an object is an instance of a particular class.

Q30. What is the primary purpose of the 'try-with-resources' statement in Java?

1. Releases system resources acquired within a try block.
2. Catches exceptions thrown within a try block.
3. Ensures that a block of code is executed.
4. Marks a block of code as synchronized.

Answer: A. Releases system resources acquired within a try block.

Q31. What does the 'static initializer' block in Java do?

1. Executes whenever an instance of the Class is created.
2. Initializes static variables of a class.
3. Executes before the main method.
4. Defines the superclass of a class.

Answer: B. Initializes static variables of a class.

Q32. What does the 'break' statement do in Java?

1. Terminates the current loop or switch statement.
2. Continues to the next iteration of a loop.
3. Skips the remainder of the current iteration and jumps to the next iteration.
4. Throws an exception to exit a method.

Answer: A. Terminates the current loop or switch statement.

Q33. What is the purpose of the ' Class.forName()' method in Java?

1. Loads a class dynamically at runtime.
2. Retrieves the superclass of a class.
3. Check if an object is an instance of a specific class.
4. Initializes a class.

Answer: A. Loads a class dynamically at runtime.

Q34. What is the purpose of the 'try-with-resources' statement in Java?

1. Manages resources by automatically closing them when they are no longer needed.
2. Catches exceptions thrown within a try block.
3. Executes a block of code repeatedly.
4. Specifies the resources available to a class.

Answer: A. Manages resources by automatically closing them when they are no longer needed.

Q35. In Java, what is a 'stream' primarily used for?

1. Managing user input/output.
2. Storing collections of data.
3. Performing operations on sequences of elements.
4. Representing graphics on a display.

Answer: C. Performing operations on sequences of elements.

Q36. What is the purpose of the 'default' keyword in Java interfaces?

1. Specifies a default value for a variable.
2. Marks a method as the default implementation in an interface.
3. Indicates the default package for a class.
4. Defines the default behavior of a class.

Answer: B. Marks a method as the default implementation in an interface.

Q37. In Java, what does the 'strictfp' keyword indicate?

1. Forces strict adherence to the Java naming conventions.
2. Specifies that a method cannot be overridden.
3. Ensures consistent floating-point arithmetic across different platforms.
4. Marks a variable as static and final.

Answer: B. Ensures consistent floating-point arithmetic across different platforms.

Q38. What is the purpose of the 'compareTo()' method in Java?

1. Compares two strings lexicographically.
2. Compares two objects for equality.
3. Compares the memory addresses of two objects.
4. Compares the sizes of two arrays.

Answer: A. Compares two strings lexicographically.

Q39. What does the 'break' statement do in a Java switch statement?

1. Exit the loop or switch statement.
2. Continues to the next iteration of the loop.
3. Skips the current iteration of the loop.
4. Throws an exception.

Answer: A. Exit the loop or switch statement.

Q40. Which Java collection class guarantees the insertion order of elements?

1. HashSet
2. TreeMap
3. LinkedHashMap
4. TreeSet

Answer: C. LinkedHashMap

Q41. What is the primary purpose of lambda expressions in Java?

1. Defining anonymous classes.
2. Implementing functional interfaces concisely.
3. Controlling access to class members.
4. Declaring static methods.

Answer: B. Implementing functional interfaces concisely.

Q42. In Java, what does the 'assert' keyword do?

1. Checks if a condition is true and throws an exception if it's false.
2. Marks a variable as immutable.
3. Signals the end of a method's execution.
4. Indicates that a method is abstract.

Answer: A. Checks if a condition is true and throws an exception if it's false.

Q43. What is the purpose of the 'enum' keyword in Java?

1. Specifies a default value for a variable.
2. Denotes a variable as immutable.
3. Defines a group of constants.
4. Indicates a method as synchronized.

Answer: C. Defines a group of constants.

Q44. What does the 'finalize()' method in Java primarily do?

1. Cleans up system resources before an object is garbage collected.
2. Marks a method as deprecated.
3. Signals at the end of a program's execution.
4. Throws an exception when a condition is not met.

Answer: A. Cleans up system resources before an object is garbage collected.

Q45. What does "boxing" refer to in Java?

1. Converting a primitive type to its corresponding wrapper class object.
2. Enclosing code within a block.
3. Creating a deep copy of an object.
4. Executing multiple threads simultaneously.

Answer: A. Converting a primitive type to its corresponding wrapper class object.

Q46. What is the primary role of the 'StringBuilder' class in Java?

1. Represents an immutable sequence of characters.
2. Provides methods for string manipulation with mutability.
3. Offers formatting for numeric values.
4. Manages synchronization in multithreaded applications.

Answer: B. Provides methods for string manipulation with mutability.

Q47. How does the 'for each' loop differ from a regular 'for' loop in Java?

1. It is used exclusively for arrays.
2. It doesn't require an explicit loop variable or index.
3. It only works with collections.
4. It can only iterate backward.

Answer: B. It doesn't require an explicit loop variable or index.

Q48. What does the 'continue' statement do in a Java loop?

1. Exits the loop.
2. Skips the remaining code in the loop and moves to the next iteration.
3. Start the loop from the beginning.
4. Halts the execution of the program.

Answer: B. Skips the remaining code in the loop and moves to the next iteration.

Q49. What is the primary purpose of Math. random()' method in Java?

1. Generates a random boolean value.
2. Produces a random integer.
3. Returns a random floating-point number between 0.0 and 1.0.
4. Creates a random character.

Answer: C. Returns a random floating-point number between 0.0 and 1.0.

Q50. What is a 'try-with-resources' statement used for in Java?

1. Declaring variables with limited scope.
2. Efficiently handling exceptions in a try block.
3. Managing and automatically closing external resources.
4. Defining custom exception classes.

Answer: B. Managing and automatically closing external resources.

Q51. What is the purpose of the 'default' keyword in a Java switch statement?

1. Specifies the default value for a case.
2. Marks a method as the default implementation in an interface.
3. Defines the default behavior if no case matches.
4. Indicates the default package for a class.

Answer: C. Defines the default behavior if no case matches.

Q52. What does the 'StringBuffer' class provide in Java?

1. Immutable strings with efficient manipulation methods.
2. Mutable strings with synchronization for multithreading.
3. Methods for comparing string values.
4. Formatting options for numeric values.

Answer: B. Mutable strings with synchronization for multithreading.

Q53. What does the 'instance of' operator check in Java?

1. If a variable is uninitialized.
2. If a variable is equal to null.
3. If an object is an instance of a specific class or its subclasses.
4. If a variable is a primitive type.

Answer:  C. If an object is an instance of a specific class or its subclasses.

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FAQs: Advanced Java MCQs

Why is Java popular?
Java is popular because it's platform-independent, reliable, and has strong community support.

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What is the salary of a Java developer?
A Java developer earns an average salary of $111,963 per year in the USA.

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