Java String Connection Performance

Sword Word has 19 kinds of writing, Java String Connection also has a good many writing, for example, to connect 6 strings, the following 5 ways to be written are OK, which is the most concise, which is the most efficient.

Public static String Concat1 (string s1, String s2, String s3, String S4, String s5, String S6) {
String result = "";
Result = S1;
Result = s2;
Result = S3;
Result = S4;
Result = S5;
Result = S6;
return result ;
    }

Public static String Concat2 (string s1, String s2, String s3, String S4, String s5, String S6) {
stringbuffer result = new StringBuffer ();
result.append (S1);
result.append (S2);
Result.appen

<