Java Basics Challenge

What are the four main data types in Java?

• decimal, integer, character, pointer

• string, object, array, list

• byte, short, int, long

• float, double, char, boolean

How do you declare a variable in Java?

• declare ;

• = ;

• : ;

• To declare a variable in Java, use the syntax: ; = ;

What is the purpose of the 'if' statement in Java?

• The purpose of the 'if' statement in Java is to execute code conditionally based on a boolean expression.

• To define a variable in Java.

• To import libraries in Java.

• To create a loop in Java.

Explain the concept of inheritance in Java.

• Inheritance in Java allows a subclass to inherit properties and methods from a superclass, promoting code reuse and establishing a hierarchical relationship.

• Inheritance in Java is used to define interfaces only.

• Inheritance allows a class to create multiple instances of itself.

• Inheritance restricts access to superclass methods and properties.

What is a try-catch block used for in Java?

• To define variables in a method.

• To improve code readability.

• To handle exceptions and prevent program crashes.

• To create new classes in Java.

Name two types of collections in the Java Collections Framework.

• Map, Queue

• Array, Stack

• Tree, Graph

• List, Set

How do you read data from a file in Java?

• Use Scanner to read data from a file.

• Use PrintWriter to write data to a file.

• Use FileReader and BufferedReader to read data from a file.

• Use FileInputStream to read data from a file.

What is the difference between 'ArrayList' and 'LinkedList'?

• LinkedList is faster for random access than ArrayList.

• ArrayList uses more memory than LinkedList for all operations.

• ArrayList is faster for random access, while LinkedList is better for frequent insertions and deletions.

• ArrayList allows for easier traversal than LinkedList.

What is the default value of a boolean variable in Java?

• true

• 1

• false

• null

How do you handle exceptions in Java?

• Log exceptions to a file without handling them.

• Use if-else statements to handle exceptions.

• Use try-catch blocks to handle exceptions.

• Ignore exceptions and continue execution.