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Java Non-Primitive Data Types

Non-primitive data types in Java are also known as reference types because they refer to objects. Unlike primitive types, non-primitive types are created by the programmer and are not defined by Java (except for String).

Key Topics

1. Strings

The String class is used to store a sequence of characters. Strings are widely used in Java programming.

String greeting = "Hello, World!";
System.out.println(greeting);

2. Arrays

An array is a container that holds a fixed number of values of a single type.

int[] numbers = {1, 2, 3, 4, 5};
System.out.println(numbers[0]); // Prints: 1

3. Classes and Objects

Classes are blueprints for creating objects. Objects are instances of classes.

public class Person {
    String name;
    int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void displayInfo() {
        System.out.println("Name: " + name + ", Age: " + age);
    }
}

public class Main {
    public static void main(String[] args) {
        Person person = new Person("Alice", 30);
        person.displayInfo();
    }
}

Output:

Name: Alice, Age: 30

Key Takeaways

  • Non-primitive types are created by the programmer and can be used to create complex data structures.
  • They store references to the memory location where the data is stored.
  • Understanding non-primitive types is essential for object-oriented programming in Java.
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