02-java-data-types.md

Java Data Types

In Java, data types specify the type of data that a variable can hold. Java has two categories of data types: primitive data types and reference data types.

Primitive Data Types

1. Numeric Types:

• int: Used for storing integer values.

  int age = 25;

• double: Used for storing floating-point numbers.

  double salary = 1200.50;

• float: Similar to double but with less precision.

  float weight = 68.5f;

• short: Used for small integers.

  short temperature = -10;

• long: Used for large integers.

  long population = 7000000000L;

2. Boolean Type:

• boolean: Used for storing true or false values.

  boolean isJavaFun = true;

3. Character Type:

• char: Used for storing a single character.

  char grade = 'A';

Reference Data Types

1. Object Types:

• String: Represents a sequence of characters.

  String greeting = "Hello, World!";

2. Arrays:

• Used for storing multiple values of the same type.

  int[] numbers = {1, 2, 3, 4, 5};

3. Custom Classes:

• User-defined classes can be used to create objects with specific data types.

  class Person {
      String name;
      int age;
  }
  
  Person john = new Person();
  john.name = "John";
  john.age = 30;