Java Program to Concat Strings

Write a Java program to Concat Strings with an example. There are multiple ways to perform string concatenation, and we cover most of them. We can use the built-in functions, including concat, StringBuilder, and StringBuffer append functions. Apart from these, use the arithmetic + operator to achieve the same.

Java Program to Concat Strings

In this Java example, we used the String function to concat con_str2 to the con_str1 and assigned the output to a new one, str3.

import java.util.Scanner;

public class Example {
	private static Scanner sc;
	
	public static void main(String[] args) {
		String con_str1;
		String con_str2;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter the first :  ");
		con_str1 = sc.nextLine();
		
		System.out.print("\nPlease Enter the second :  ");
		con_str2 = sc.nextLine();
		
		String str3 = con_str1.concat(con_str2);
		
		System.out.println("\nThe result  =  " + str3);
	}
}

Please Enter the first :  Hi

Please Enter the second :  Hello

The result  =  HiHello

Using Assignment Operator +

In this Program, we used the Assignment Operator + for String concatenation. By default, the + operator will concat the given strings. However, to add the space between the two words, you must use the ‘ ‘ between the words.

import java.util.Scanner;

public class ConcatStrings1 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		String conStr1;
		String conStr2;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter the first String :  ");
		conStr1 = sc.nextLine();
		
		System.out.print("\nPlease Enter the second String :  ");
		conStr2 = sc.nextLine();
		
		String str3 = conStr1 + ' ' + conStr2;
		
		System.out.println("\nThe Java String concat result  =  " + str3);
	}
}

Java Program to Concat Strings using StringBuilder

The StringBuilder has an append function that appends one string at the end of the other one.

import java.util.Scanner;

public class Example2 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		String conStr1;
		String conStr2;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter the first :  ");
		conStr1 = sc.nextLine();
		
		System.out.print("\nPlease Enter the second :  ");
		conStr2 = sc.nextLine();
	
		StringBuilder sb = new StringBuilder(15);
		
		sb.append(conStr1).append(" ").append(conStr2);
		
		System.out.println("\nThe result  =  " + sb.toString());
	}
}

Using StringBuffer append

The StringBuffer also has an append function that concat one string to the end of the other.

import java.util.Scanner;

public class Example3 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		String conStr1;
		String conStr2;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter the first  :  ");
		conStr1 = sc.nextLine();
		
		System.out.print("\nPlease Enter the second :  ");
		conStr2 = sc.nextLine();
	
		StringBuffer sbuff = new StringBuffer(15);
		
		sbuff.append(conStr1).append(" ").append(conStr2);
		
		System.out.println("\nResult  =  " + sbuff.toString());
	}
}