20 Jul Java Methods

A method is an organized block of reusable code that avoids repeating tasks again and again. If you want to do a task repeatedly in code, then just make a method, set the task in it, and call the method multiple times whenever you need it. Methods are also known as Functions.

Types of Methods in Java

1. Pre-defined: Eg: println(), concat(), equals(), etc.
2. User-defined: Custom methods created by the programmer for custom tasks.

Let us see how to:

• Create and call a method.
• Method Declaration and Definition
• Method Parameters
• Multiple Parameters

Create and call a Method in Java – Example 1

To create a function in Java, set the name of the function followed by parentheses. Our method is demoMethod():

public static void demoMethod() {
  // write the code
}

A function in Java gets executed when it is called:

demoMethod()

Let us now see an example of creating a method in Java:

// Create and call a Function (Method) in Java
class Studyopedia {

    /* We add the static keyword in Java so that a method belongs to the class itself,
     rather than to individual objects created from that class */
    /* A static method is tied to the class itself. Even if no object of Demo105 exists,
     the method can still be executed.
     */
    // Function Definition
    static void demoMethod() {
        System.out.println("This is a demo method in Java.");
    }
    public static void main(String[] args) {
        // Function call
        demoMethod();
    }
}

Output

This is a demo method in Java.

Method Declaration and Definition

In the above example, we saw how to create and call a method in Java. We defined and declared the method as well:

public static void demoMethod() { // method declaration
  // method definition
}

A method in Java gets executed when it is called:

demoMethod()

Method Parameters in Java – Example 2

Set the parameters in a Java method after the name of the method. For example:

static void demoMethod(int rank) { }

To call a method with a parameter, set the value of the variable while calling, for example:

demoMethod(5)

Therefore, we have passed the rank with the value 5 while calling the above.

Let us now see an example of creating a Method and passing a parameter in Java:

// Function (Method) Parameters in Java
class Studyopedia {

    /* We add the static keyword in Java so that a method belongs to the class itself,
     rather than to individual objects created from that class */
    /* A static method is tied to the class itself. Even if no object of class Studyopedia exists,
     the method can still be executed.
     */
    // Function Definition with rank parameter
    static void demoMethod(int rank) {
        System.out.println("This is a demo method in Java.");
        System.out.println("Rank = "+rank);
    }
    public static void main(String[] args) {
        // Function call with 5 as an argument
        demoMethod(5);
    }
}

Output

This is a demo method in Java.
Rank = 5

Multiple Parameters in a Method in Java

We can also set more than one parameter in a function in Java. For example:

static void demoMethod(string player, int rank, int points)

To call a function with multiple parameters, set the value of the variable while calling, for example:

demoMethod("Amit", 1, 95)

We have passed the following multiple parameters while calling the above:

• player: Amit
• rank: 1
• points: 95

Let us now see an example of creating a Method and passing multiple parameters:

// Function (Method) with Multiple Parameters in Java

class Demo107 {

    /* We add the static keyword in Java so that a method belongs to the class itself,
     rather than to individual objects created from that class */
    /* A static method is tied to the class itself. Even if no object of Demo105 exists,
     the method can still be executed.
     */
    // Function Definition with player, rank, and points parameter
    static void demoMethod(String player, int rank, int points) {
        System.out.println("\nThis is a demo method in Java.");
        System.out.println("Player = "+player);
        System.out.println("Rank = "+rank);
        System.out.println("Points = "+points);

    }
    public static void main(String[] args) {

        // Function call with 3 arguments
        demoMethod("Amit", 1, 95);
        demoMethod("Steve", 2, 90);
        demoMethod("David", 3, 80);
    }
}

Output

This is a demo method in Java.
Player = Amit
Rank = 1
Points = 95

This is a demo method in Java.
Player = Steve
Rank = 2
Points = 90

This is a demo method in Java.
Player = David
Rank = 3
Points = 80

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