import java.io.*;
import java.lang.*;
class Concatenation
{
    public static void main(String args[])throws IOException
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String s1,s2;
        System.out.println("Enter First String: ");
        s1=br.readLine();
        System.out.println("Enter Second String: ");
        s2=br.readLine();
        System.out.println("Concatination of s1 and s2 :"+s1.concat(s2));
    }
}

 OUTPUT:

Compile: javac Concatenation.java
 
Run: java Concatenation
 
Enter First String:
Sowji
Enter Second String:
Kutti
Concatination of s1 and s2 :SowjiKutti