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Java MCQ: Which of the following is not a reserved keyword in Java? a) const b) goto c) implements d) sizeof Answer: d) sizeof Explanation: The sizeof keyword is not a reserved keyword in Java. It is used in C and C++ to determine the size of a data type or variable, but Java does […]

Java MCQ: Which of the following methods is used to start a thread in Java? a) run() b) start() c) execute() d) init() Answer: b) start() Explanation: In Java, the start() method is used to begin the execution of a thread. When start() is called, the Java Virtual Machine (JVM) creates a new thread of

Java MCQ: Which of the following is not a feature of Java? a) Platform-independent b) Object-oriented c) Pointers d) Secure Answer: c) Pointers Explanation: Java is a platform-independent, object-oriented, and secure programming language, but it does not support pointers. Pointers are used in languages like C and C++ to directly access memory addresses, but Java

Java MCQ: Which of the following is true about interfaces in Java? a) Interfaces can contain default methods b) Interfaces can contain abstract methods c) Interfaces cannot have instance variables d) All of the above Answer: d) All of the above Explanation: In Java, interfaces are used to define a contract that classes can implement.

Java MCQ: Which of the following is not a valid Java identifier? a) myVariable b) $myVariable c) _myVariable d) 1myVariable Answer: d) 1myVariable Explanation: In Java, an identifier is a name given to a variable, method, class, or any other user-defined item. Identifiers must follow certain rules: they can start with a letter, underscore (_),

Java MCQ: Which of the following can be used to create an object in Java? a) new b) malloc c) alloc d) calloc Answer: a) new Explanation: In Java, the new keyword is used to create an object of a class. It dynamically allocates memory for the object and returns a reference to it. For

Java MCQ: Which method is called by the garbage collector in Java? a) dispose() b) finalize() c) destructor() d) delete() Answer: b) finalize() Explanation: In Java, the finalize() method is called by the garbage collector just before an object is destroyed. This method provides an opportunity for the object to clean up resources, such as

Java MCQ: What is the purpose of the ‘final’ keyword in Java? a) To prevent inheritance of a class b) To prevent method overriding c) To declare constants d) All of the above Answer: d) All of the above Explanation: The final keyword in Java serves multiple purposes. It can be used to prevent inheritance

Java MCQ: Which of the following statements is true about constructors in Java? a) Constructors can be abstract b) Constructors can be final c) Constructors cannot be synchronized d) Constructors do not return any value Answer: d) Constructors do not return any value Explanation: Constructors in Java are special methods used to initialize objects. They

Java MCQ: Which of the following is used to define a block of code that can handle exceptions in Java? a) try block b) catch block c) finally block d) All of the above Answer: d) All of the above Explanation: In Java, exception handling involves several constructs, including the try, catch, and finally blocks.

Java MCQ: Which of the following is a checked exception in Java? a) NullPointerException b) IOException c) ArithmeticException d) ArrayIndexOutOfBoundsException Answer: b) IOException Explanation: In Java, exceptions are categorized into two main types: checked exceptions and unchecked exceptions. Checked exceptions are exceptions that must be either caught or declared in the method signature using the

Java MCQ: Which of the following is a marker interface in Java? a) Serializable b) Runnable c) Cloneable d) Both a and c Answer: d) Both a and c Explanation: In Java, a marker interface is an interface that does not contain any methods or fields. Its purpose is to provide metadata to the Java

Java MCQ: What does the ‘super’ keyword do in Java? a) It refers to the superclass b) It creates a new object c) It overrides a method d) It finalizes an object Answer: a) It refers to the superclass Explanation: In Java, the super keyword is used to refer to the superclass (parent class) of

Java MCQ: What is the result of 10 + 20 + “30” in Java? a) 1030 b) 30 c) 102030 d) 3030 Answer: d) 3030 Explanation: In Java, the expression 10 + 20 + "30" results in "3030". This is because Java evaluates the expression from left to right. Initially, it adds 10 and 20,

Java MCQ: Which of the following loops is guaranteed to execute at least once? a) for loop b) while loop c) do-while loop d) None of the above Answer: c) do-while loop Explanation: The do-while loop in Java is a type of loop that is guaranteed to execute at least once, regardless of whether the

Java MCQ: Which keyword is used to create a constant variable in Java? a) final b) const c) static d) constant Answer: a) final Explanation: In Java, the final keyword is used to create a constant variable, meaning that the variable’s value cannot be changed once it has been assigned. This makes the variable immutable,

Java MCQ: Which of the following is used to handle exceptions in Java? a) if-else b) for loop c) switch-case d) try-catch Answer: d) try-catch Explanation: In Java, exceptions are handled using the try-catch block. When an exception occurs in the try block, the control is transferred to the catch block where the exception is

Java MCQ: What is the correct syntax to declare a main method in Java? a) public static int main(String[] args) b) public static void main(String[] args) c) public void main(String[] args) d) static void main(String[] args) Answer: b) public static void main(String[] args) Explanation: The main method in Java is the entry point of any

Java MCQ: Which of the following statements is true about Java packages? a) A package is a way to organize classes in Java b) Packages are used to prevent naming conflicts c) Packages can be nested inside other packages d) All of the above Answer: d) All of the above Explanation: Java packages serve as

Java MCQ: Which of the following is the correct way to declare a variable in Java? a) int 1x = 10; b) int x = 10; c) float x = 1.0; d) string x = “Hello”; Answer: b) int x = 10; Explanation: In Java, variable declaration follows specific syntax rules. The correct way to

Java MCQ: Which method is used to compare two strings in Java for equality? a) equals() b) compare() c) compareTo() d) == Answer: a) equals() Explanation: In Java, the equals() method is used to compare two strings for equality. This method compares the content of the strings, character by character, and returns true if the

Java MCQ: What is the default value of a local variable in Java? a) 0 b) null c) undefined d) Local variables do not have a default value Answer: d) Local variables do not have a default value Explanation: In Java, local variables are those declared within a method, constructor, or block, and they are

Java MCQ: What is the default value of a boolean variable in Java? a) true b) false c) 0 d) null Answer: b) false Explanation: In Java, when a boolean variable is declared as an instance variable (a member of a class) and is not explicitly initialized, it is automatically assigned a default value. For

Java MCQ: Which keyword is used to inherit a class in Java? a) implement b) extends c) inherits d) derived Answer: b) extends Explanation: The keyword extends in Java is used to inherit a class, meaning that it allows one class to take on the properties and methods of another. This is a key feature

Java MCQ: Which method must be implemented by all threads in Java? a) run() b) start() c) execute() d) stop() Answer: a) run() Explanation: In Java, the run() method is the entry point for executing code in a thread. Every thread in Java is associated with an instance of a class that implements the Runnable