Java Concepts Assessment For J.A

What method would you use to add an element to an ArrayList?

• Use the 'insert' method.

• Use the 'append' method.

• Use the 'add' method.

• Use the 'push' method.

Provide an example of method overloading in Java.

• class Calculator { double add(int a, double b) { return a + b; } }

• Example of method overloading: class Calculator { int add(int a, int b) { return a + b; } double add(double a, double b) { return a + b; } int add(int a, int b, int c) { return a + b + c; } }

• class Calculator { void add(int a, int b) { return; } }

• class Calculator { int add(int a) { return a; } }

Explain the concept of method overriding in inheritance.

• Method overriding is when a superclass changes the implementation of a method in its subclass.

• Method overriding prevents subclasses from using methods defined in their superclasses.

• Method overriding is a way to create new methods in a subclass without affecting the superclass.

• Method overriding allows a subclass to provide a specific implementation of a method already defined in its superclass, enabling customized behavior.

What is the purpose of a try-catch block in exception handling?

• The purpose of a try-catch block is to handle exceptions and prevent program crashes.

• To optimize the performance of the code.

• To define global variables for the program.

• To improve code readability and maintainability.

Write a for loop that prints numbers from 1 to 10.

• for (i = 1; i < 10; i++) { console.log(i); }

• for (let i = 1; i <= 10; i++) { console.log(i); }

• for (let i = 1; i <= 5; i++) { console.log(i); }

• for (let i = 0; i < 10; i++) { console.log(i + 1); }

What is inheritance in Java? Give an example.

• For example, if we have a superclass 'Animal' with a method 'makeSound()', a subclass 'Dog' can inherit this method and provide its own implementation.

• Inheritance is a way to create multiple instances of a class.

• Inheritance allows a subclass to override methods from its superclass.

• Inheritance is used to define interfaces in Java.

What is the difference between pre-increment and post-increment operators?

• Pre-increment modifies the variable before use; post-increment modifies it after use.

• Pre-increment and post-increment are the same.

• Pre-increment is used only in loops.

• Post-increment can only be used with integers.

Define a class and create an object of that class in Java.

• class MyClass { } MyClass myObject;

• MyClass myObject = new MyClass;

• class MyClass {} MyClass myObject = new MyClass();

• class MyClass() {} MyClass myObject = new MyClass();

What are the different types of variables in Java?

• Global Variables

• Temporary Variables

• Dynamic Variables

• Local Variables, Instance Variables, Static Variables, Parameters

How do you declare an ArrayList in Java?

• ArrayList listName = new ArrayList();

• ArrayList listName = ArrayList<>();

• ArrayList listName = new ArrayList<>();

• ArrayList listName = new ArrayList();