JAVA Tutorial

🔸 Data Types in Java

Data types in Java define the type of a variable. They specify what kind of data a variable can hold. Java is a strongly-typed language, meaning that each variable must be declared with a specific data type. Java provides two types of data types: Primitive and Non-Primitive data types.

🔹 Primitive Data Types

Primitive data types are the most basic types of data available in Java. They represent single values and are predefined by the language. Java supports eight primitive data types:

• byte: 8-bit integer. Range: -128 to 127
• short: 16-bit integer. Range: -32,768 to 32,767
• int: 32-bit integer. Range: -2^31 to 2^31-1
• long: 64-bit integer. Range: -2^63 to 2^63-1
• float: 32-bit floating-point. For decimals, up to 7 digits of precision
• double: 64-bit floating-point. For decimals, up to 15 digits of precision
• char: 16-bit Unicode character. Represents a single character
• boolean: Represents one of two values: true or false

🔸 Example of Primitive Data Types

// Example of Primitive Data Types in Java

public class DataTypesExample {
  public static void main(String[] args) {
    byte b = 100;    // 8-bit integer
    short s = 5000;  // 16-bit integer
    int i = 100000;  // 32-bit integer
    long l = 1000000000L;  // 64-bit integer (L is added to specify long)

    float f = 5.75f;   // 32-bit floating point (f is added)
    double d = 19.99;   // 64-bit floating point

    char c = 'A';    // 16-bit Unicode character
    boolean isJavaFun = true;   // boolean value

    System.out.println("Byte value: " + b);
    System.out.println("Short value: " + s);
    System.out.println("Int value: " + i);
    System.out.println("Long value: " + l);
    System.out.println("Float value: " + f);
    System.out.println("Double value: " + d);
    System.out.println("Char value: " + c);
    System.out.println("Is Java fun? " + isJavaFun);
  }
}
  

🔹 Non-Primitive Data Types

Non-primitive data types, also known as reference types, are used to store references to objects. These are more complex data types and are defined by the user. Examples include:

• String: Used to store a sequence of characters (text). It is one of the most commonly used non-primitive types in Java.
• Arrays: Used to store multiple values of the same type in a single variable.
• Classes: Custom data types defined by the user, which can contain fields, methods, and constructors.
• Interfaces: Reference types that define methods to be implemented by classes.

🔸 Example of Non-Primitive Data Types

// Example of Non-Primitive Data Types in Java

public class NonPrimitiveExample {
  public static void main(String[] args) {
    String greeting = "Hello, World!";  // String (non-primitive)
    int[] numbers = {1, 2, 3, 4, 5};  // Array of integers (non-primitive)

    System.out.println("Greeting message: " + greeting);
    System.out.println("Array elements: ");
    for (int num : numbers) {
      System.out.print(num + " ");
    }
  }
}
  

🔸 Key Points to Remember

• Primitive data types store simple values and are more memory-efficient.
• Non-primitive data types store references to objects or data structures.
• Each data type has a default value. For example, an int defaults to 0, and a boolean defaults to false.