Day-58 Java Basics: Static, Non-Static, Objects, Methods, Return Types

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Static and Non-Static

In Java, static is used when something belongs to the class itself. It is common for all objects. Non-static is used when something belongs to a particular object. It is different for each object created from the class.

Example:

public class Home
{
    // non-static: object specific information
    String name1 = "dhanush";
    int age1 = 25;

    // static: class specific information
    static String name2 = "tamil";
    static int age2 = 15;

    public static void main(String[] ramesh)
    {
        System.out.println(Home.name2);
        System.out.println(Home.age2);

        Home person = new Home(); // new object
        System.out.println(person.name1);
        System.out.println(person.age1);
    }
}

Objects

An object is created from a class using the new keyword. It creates space in memory to store data and methods defined in the class.

Example:

Home person = new Home();

Methods

Methods are sets of instructions grouped together with a name. They are used to perform specific tasks. Methods can be reused and called again whenever needed.

Example:

public class Shop
{
    static String shopName = "seenu";
    String product_name = "pen";
    int product_price = 10;

    public static void main(String[] args)
    {
        Shop product = new Shop();

        // method calling statement  
        String greeting = product.buy();
        System.out.println(greeting);
    }

    String buy()
    {
        System.out.println("buy method");
        return "thank you";
    }
}

Return Types

Methods have return types. If a method does not return anything, we use void in its declaration. If a method returns something, we mention its datatype. The return keyword is used to send back a value from the method, which can be stored in a variable for later use.

In the above example: