String concatenation in java

                                    public class Concat {
    String cat(String a, String b) {
        a += b;
        return a;
    }
}

                                    String s="Sachin"+" Tendulkar";  
   System.out.println(s);//Sachin Tendulkar  

Output:Sachin Tendulkar

                                    // StringBuilder
String stringBuilderConcat = new StringBuilder()
    .append(greeting)
    .append(" ")
    .append(person)
    .append("! Welcome to the ")
    .append(location)
    .append("!")
    .build();

                                    public class ConcatenationExample {
   public static void main(String args[]) {
       //One way of doing concatenation
       String str1 = "Welcome";
       str1 = str1.concat(" to ");
       str1 = str1.concat(" String handling ");
       System.out.println(str1);

       //Other way of doing concatenation in one line
       String str2 = "This";
       str2 = str2.concat(" is").concat(" just a").concat(" String");
       System.out.println(str2);
   }
}