Java Programming

Java MCQ: Which of the following is not a method in the ‘String’ class? a) length() b) substring() c) equalsIgnoreCase() d) size() Answer: d) size() Explanation: The Java String class provides a variety of methods for manipulating and inspecting strings. Common methods include length() for getting the length of the string, substring() for extracting a […]

Java MCQ: Which of the following is true about Java’s ‘enum’ keyword? a) ‘enum’ is used to define a collection of constants b) Enums in Java can have methods c) Enum constants are implicitly static and final d) All of the above Answer: d) All of the above Explanation: In Java, the enum keyword is

Java MCQ: Which of the following is not a valid method for converting a string to an integer in Java? a) Integer.parseInt() b) Integer.valueOf() c) String.toInt() d) None of the above Answer: c) String.toInt() Explanation: In Java, there are several ways to convert a string to an integer. The Integer.parseInt() method is commonly used to

Java MCQ: Which of the following is true about the ‘this’ keyword in Java? a) ‘this’ is used to refer to the current object b) ‘this’ can be used to invoke another constructor in the same class c) ‘this’ can be passed as an argument in the method call d) All of the above Answer:

Java MCQ: Which of the following is the default value of a local variable in Java? a) null b) 0 c) false 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 variables that are declared within a method, constructor,

Java MCQ: Which of the following is not a feature of Java? a) Dynamic b) Platform-independent c) Machine-dependent d) Multithreaded Answer: c) Machine-dependent Explanation: Java is designed to be platform-independent, meaning that Java programs can run on any device or operating system that has the Java Virtual Machine (JVM) installed. This “write once, run anywhere”

Java MCQ: Which of the following is used to compare the contents of two objects in Java? a) == operator b) equals() method c) compareTo() method d) hashCode() method Answer: b) equals() method Explanation: In Java, the equals() method is used to compare the contents of two objects. Unlike the == operator, which compares the

Java MCQ: Which of the following is a wrapper class in Java? a) int b) Integer c) float d) boolean Answer: b) Integer Explanation: In Java, a wrapper class is an object representation of a primitive data type. The Integer class is a wrapper class for the primitive data type int. Wrapper classes provide a

Java MCQ: Which of the following is true about the ‘abstract’ keyword in Java? a) Abstract classes cannot be instantiated b) Abstract methods do not have a body c) A class must be declared abstract if it contains abstract methods d) All of the above Answer: d) All of the above Explanation: The abstract keyword

Java MCQ: Which of the following interfaces is used to handle events in Java? a) Runnable b) Serializable c) EventListener d) Cloneable Answer: c) EventListener Explanation: The EventListener interface in Java is used to handle events. It is a marker interface that all event listener interfaces must extend. Event listeners are objects that are notified

Java MCQ: Which of the following is not a type of inheritance in Java? a) Single inheritance b) Multiple inheritance through classes c) Multilevel inheritance d) Hierarchical inheritance Answer: b) Multiple inheritance through classes Explanation: In Java, multiple inheritance through classes is not supported. This means a class cannot inherit from more than one class.

Java MCQ: Which of the following is true about Java’s ‘String’ class? a) Strings are immutable b) Strings can be changed after they are created c) Strings are a primitive data type d) Strings are thread-unsafe by default Answer: a) Strings are immutable Explanation: In Java, the String class represents a sequence of characters. One

Java MCQ: Which of the following statements about Java arrays is true? a) Arrays are of fixed size b) Arrays can hold primitive types as well as objects c) Array indices start at 0 d) All of the above Answer: d) All of the above Explanation: Java arrays have several key characteristics. They are of

Java MCQ: Which of the following statements is true about the ‘static’ keyword in Java? a) Static methods can access instance variables directly b) Static methods belong to the class, not instances c) Static methods can override instance methods d) Static methods can be abstract Answer: b) Static methods belong to the class, not instances

Java MCQ: Which access modifier is used to allow access to members of a class within the same package but not from outside? a) private b) protected c) public d) default Answer: d) default Explanation: In Java, when no access modifier is specified for a class member, the default access level is package-private, also known

Java MCQ: What is the output of the following code snippet? public class Test { public static void main(String[] args) { int x = 5; int y = ++x * 5 / x– + –x; System.out.println(“y = ” + y); } } a) y = 5 b) y = 6 c) y = 7 d)

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