Non-Primitive Data Types in Java

Data types are basically used for declaring variables and functions of different types. It can define different sizes and values which are used to store variables. Non-primitive data types are also called reference types. This is because these data types are directly referred to as objects. It means like primitive data types these data types are not pre-defined. These are popular for user-defined which are created by programmers. There are various types of non-primitive data types in java i.e.:
Class
Object
String
Array
Interface

Variable, Constant & Literals in JAVA

A variable is a data name that is used for storing a data value. The value of the variable may be changed during the program execution, Example: – int number = 8; Here ‘int’ is a data type, ‘number’ is a variable name and 8 is a value that it stores.

Structure of Java Program

Structure of Java Program There are various concepts used in a java program i.e.: Classes
Objects
Packages
Methods
Interface
OOPs Concept
Exception Handling
Multi-Threading
Collection Framework