Java Program to Concatenate two Strings

In this tutorial, we are going to learn java program to concatenate two strings together.

For two input strings that are given by the user, we need to join them together and return the final string as an output.

For example

Case1: If the user gives the strings ‘java’ and ‘program’

                    then the output should be ‘javafun’.

Case2: If the user gives the inputs as ‘learn’ and ‘java’,

                    then the output should be ‘learnjava’.

Program 1: Concatenate two Strings using ‘+’ Operator in Java

import java.util.*;
public class Main
{
    public static void main (String[]args){
        System.out.println("Java program to concatenate String using +");
        Scanner sc = new Scanner (System.in);
        System.out.println ("Please enter First String");
        String str1 = sc.nextLine(); 
        System.out.println ("Please enter Second String");
        String str2 = sc.nextLine();
        String str3 = str1 + str2;
        System.out.println ("Strings after concatenation = "+str3);
    }
}

Output

Java program to concatenate String using +
Please enter First String
Quescol
Please enter Second String
Website
Strings after concatenation = QuescolWebsite

Explanations

The user is given the input ‘Quescol’ and ‘Website’, now to join them together our program used the ‘+’ operator which joins two strings together and the final string generated is ‘QuescolWebsite’.

Program 2: Concatenate two Strings using join() method in Java

import java.util.*;
public class Main
{
    public static void main (String[]args){
        System.out.println("Java program to concatenate String using String.join() Java 8");
        Scanner sc = new Scanner (System.in);
        System.out.println ("Please enter First String");
        String str1 = sc.nextLine(); 
        System.out.println ("Please enter Second String");
        String str2 = sc.nextLine(); 
        String str3 = String.join("",str1,str2);
        System.out.println ("Strings after concatenation = "+str3);
 	} 
}

Output

Java program to concatenate String using String.join() Java 8
Please enter First String
Quescol
Please enter Second String
Website
Strings after concatenation = QuescolWebsite

Explanations

In this example, the two strings entered by the user are ‘Quescol’ and ‘Website’ after using the join() method which took two strings as iterable and returns the output as ‘QuescolWebsite’.

Program 3 : Concatenate two Strings using concat() method in Java

import java.util.*;
public class Main
{
    public static void main (String[]args){
        System.out.println("Java program to concatenate String using concat()");
        Scanner sc = new Scanner (System.in);
        System.out.println ("Please enter First String");
        String str1 = sc.nextLine(); 
        System.out.println ("Please enter Second String");
        String str2 = sc.nextLine(); 
        String str3 = str1.concat(str2);
        System.out.println ("Strings after concatenation = "+str3);
    }
}

Output

Java program to concatenate String using concat()
Please enter First String
Quescol
Please enter Second String
Website
Strings after concatenation = QuescolWebsite

Explanations

In this example, the two strings entered by the user are ‘Quescol’ and ‘Website’ after using the concat() method which took two strings as iterable and returns the output as ‘QuescolWebsite’.