Data Types

In Java, data types are used to define the type of data a variable can hold. Data types determine the size and format of data that can be stored in a variable, as well as the operations that can be performed on that data. Java has two categories of data types: primitive data types and reference data types. In this documentation, we will explore both categories in detail.

Datatypes in Java

Primitive Data Types

Primitive data types are the fundamental data types provided by Java, and they are divided into four categories: integral, floating-point, character, and boolean. Let's take a closer look at each of these types.

Integral Data Types

1. byte

   • Size: 8 bits (1 byte)

   • Range: -128 to 127

   • Example:

     byte age = 30;

2. short

   • Size: 16 bits (2 bytes)

   • Range: -32,768 to 32,767

   • Example:

     short distance = 1000;

3. int

   • Size: 32 bits (4 bytes)

   • Range: -2^31 to 2^31-1

   • Example:

     int population = 1000000;

4. long

   • Size: 64 bits (8 bytes)

   • Range: -2^63 to 2^63-1

   • Example:

     long bigNumber = 1000000000L; // Note the 'L' suffix to indicate a long literal

Floating-Point Data Types

5. float

   • Size: 32 bits (4 bytes)

   • Example:

     float temperature = 98.6f; // Note the 'f' suffix to indicate a float literal

6. double

   • Size: 64 bits (8 bytes)

   • Example:

     double pi = 3.14159265359;

Character Data Type

7. char

   • Size: 16 bits (2 bytes)

   • Represents a single Unicode character.

   • Example:

     char grade = 'A';

Boolean Data Type

8. boolean

   • Size: JVM-dependent (commonly 1 bit)

   • Represents true or false.

   • Example:

     boolean isJavaFun = true;

Reference (Non-Primitive) Data Types

Reference data types are used to refer to objects. These data types do not store the actual data but store references to the memory location where the data is stored. Common reference data types include:

1. String

   • Used to store a sequence of characters.

   • Example:

     String greeting = "Hello, World!";

2. Arrays

   • Used to store multiple values of the same data type.

   • Example:

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

3. Classes

   • User-defined data types that can have attributes and methods.

   • Example:

     class Person {
         String name;
         int age;
     }

4. Interfaces

   • Defines a contract for implementing classes.

   • Example:

     interface Drawable {
         void draw();
     }

5. Enums

   • A special data type for a predefined set of constants.

   • Example:

     enum Day {SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY}

Understanding Java data types is essential for writing effective and efficient Java programs. You should choose the appropriate data type for your variables based on the nature of the data you intend to store. Keep in mind the size and range of the data types to prevent overflow or loss of precision.