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Java MCQ: Identify the modifier which cannot be used for constructors. a) private b) protected c) final d) public Answer: c) final Explanation: The final modifier cannot be applied to constructors in Java because constructors are not inherited, and hence, there’s no point in preventing inheritance. Other access modifiers like private, protected, and public can […]

Java MCQ: Where does the system store parameters and local variables whenever a method is invoked? a) Stack b) Heap c) Array d) LinkedList Answer: a) Stack Explanation: In Java, parameters and local variables are stored in the stack memory whenever a method is invoked. The stack memory is used for execution of a thread

Java MCQ: What is the output of Math.floor(3.6)? a) 3.0 b) 4.0 c) 3.6 d) 3 Answer: a) 3.0 Explanation: The Math.floor() method in Java returns the largest integer that is less than or equal to the argument passed. For Math.floor(3.6), it returns 3.0. Reference links: https://www.rameshfadatare.com/learn-java-programming/ https://www.javaguides.net/p/java-tutorial-learn-java-programming.html

Java MCQ: Identify the return type of a method that does not return any value. a) void b) int c) double d) null Answer: a) void Explanation: In Java, the void keyword is used as the return type of a method that does not return any value. This indicates that the method performs an action

Java MCQ: Total constructors in the String class have? a) 13 b) 10 c) 12 d) 15 Answer: c) 12 Explanation: The String class in Java has 12 constructors that allow for the creation of strings in various ways, such as from arrays of bytes, characters, and string literals. Reference links: https://www.rameshfadatare.com/learn-java-programming/ https://www.javaguides.net/p/java-tutorial-learn-java-programming.html

Java MCQ: How many String objects will be created in the following code? a) 1 b) 2 c) 3 d) 4 Answer: a) 1 Explanation: When a String is created using a string literal, only one String object is created in the string pool, if no other object with the same content exists. Reference links:

Java MCQ: compareTo() returns? a) Positive integer, zero, or negative integer b) True or false c) 1 or -1 d) None of the above Answer: a) Positive integer, zero, or negative integer Explanation: The compareTo() method in Java returns a positive integer, zero, or a negative integer based on whether the object is greater than,

Java MCQ: In which of the following is toString() method defined? a) java.lang.Object b) java.lang.String c) java.lang.util d) java.lang.Class Answer: a) java.lang.Object Explanation: The toString() method is defined in the java.lang.Object class, which is the superclass of all classes in Java. This method is often overridden to provide a string representation of an object. Reference

Java MCQ: When is the object created with the new keyword? a) At runtime b) At compile-time c) Depends on the code d) None of the above Answer: a) At runtime Explanation: In Java, objects are created at runtime when the new keyword is used. This is when memory is allocated for the new object,

Java MCQ: Arrays in Java are? a) Objects b) Primitive data types c) Methods d) None of the above Answer: a) Objects Explanation: In Java, arrays are considered objects. This means they are instances of a class, and they have a built-in field length that stores their size. Reference links: https://www.rameshfadatare.com/learn-java-programming/ https://www.javaguides.net/p/java-tutorial-learn-java-programming.html

Java MCQ: Select the valid statement to declare and initialize an array. a) int[] arr = new int[5]; b) int arr[] = new int[5]; c) int arr[] = {1, 2, 3, 4, 5}; d) All of the above Answer: d) All of the above Explanation: All the provided statements are valid ways to declare and

Java MCQ: When an array is passed to a method, what does the method receive? a) The reference of the array b) A copy of the array c) Length of the array d) Copy of the first element Answer: a) The reference of the array Explanation: When an array is passed to a method in

Java MCQ: Automatic type conversion is possible in which of the possible cases? a) When the source type is larger than the destination type b) When the source type is smaller than the destination type c) When the types are incompatible d) None of the above Answer: b) When the source type is smaller than

Java MCQ: What is the size of float and double in Java? a) 32 and 64 b) 32 and 32 c) 64 and 64 d) 64 and 32 Answer: a) 32 and 64 Explanation: In Java, a float is a 32-bit IEEE 754 floating-point, and a double is a 64-bit IEEE 754 floating-point. Float has

Java MCQ: Number of primitive data types in Java are? a) 6 b) 7 c) 8 d) 9 Answer: c) 8 Explanation: Java has 8 primitive data types: byte, short, int, long, float, double, char, and boolean. These data types serve as the building blocks for data manipulation in Java. Reference links: https://www.rameshfadatare.com/learn-java-programming/ https://www.javaguides.net/p/java-tutorial-learn-java-programming.html

Java MCQ: Which of the following is true about the LinkedHashMap class? a) It maintains insertion order b) It is a subclass of HashMap c) It allows null values d) All of the above Answer: d) All of the above Explanation: The LinkedHashMap class in Java maintains the insertion order of elements, is a subclass

Java MCQ: Which interface does PriorityQueue implement in Java? a) Queue b) List c) Set d) Map Answer: a) Queue Explanation: The PriorityQueue class in Java implements the Queue interface. It provides a way to order elements based on their priority and is part of the Java Collections Framework. Understanding the Queue interface and its

Java MCQ: What is the main difference between HashMap and Hashtable? a) HashMap is unsynchronized, Hashtable is synchronized b) HashMap allows null keys and values, Hashtable does not c) HashMap is generally faster than Hashtable d) All of the above Answer: d) All of the above Explanation: The main differences between HashMap and Hashtable are:

Java MCQ: What is a PriorityQueue in Java? a) A queue that orders elements based on their priority b) A queue that stores elements in a first-in, first-out order c) A queue that does not allow duplicates d) A queue that maintains insertion order Answer: a) A queue that orders elements based on their priority

Java MCQ: What is a Hashtable in Java? a) A synchronized map that does not allow null keys or values b) A map that maintains insertion order c) A map that allows null values d) A map that stores keys in a sorted order Answer: a) A synchronized map that does not allow null keys

Java MCQ: What is a TreeMap in Java? a) A map that stores keys in a sorted order b) A map that allows null keys c) A map that does not allow duplicate keys d) A map that uses a linked list internally Answer: a) A map that stores keys in a sorted order Explanation:

Java MCQ: What is a LinkedHashMap in Java? a) A map that maintains the insertion order of its elements b) A map that sorts keys in natural order c) A map that does not allow null values d) A map that allows duplicate keys Answer: a) A map that maintains the insertion order of its

Java MCQ: What is a HashMap in Java? a) A map that stores key-value pairs with unique keys and allows null values b) A map that stores keys in a sorted order c) A map that does not allow null keys or values d) A list that allows duplicates Answer: a) A map that stores

Java MCQ: What is the Map interface in Java? a) A collection that maps keys to values b) A collection that stores elements in a sequence c) A collection that does not allow null values d) A collection that allows duplicates Answer: a) A collection that maps keys to values Explanation: The Map interface in

Java MCQ: What is a TreeSet in Java? a) A set that stores elements in a sorted order b) A set that allows duplicates c) A set that stores key-value pairs d) A set that does not allow null elements Answer: a) A set that stores elements in a sorted order Explanation: A TreeSet in