Command not executed inside

Question

I've tried this, but i get no output. Why?
while(tokenizer.nextToken()!= StreamTokenizer.TT_EOF)
            switch(tokenizer.ttype)
                case StreamTokenizer.TT_EOL:               
                break;
                case StreamTokenizer.TT_NUMBER:
                System.out.println(s.concat(Double.toString(tokenizer.nval)));
                break;
                case StreamTokenizer.TT_WORD:
                System.out.println(s.concat(tokenizer.sval)); // Already a String
                break;
                default: // single character in ttype
                s = String.valueOf((char)tokenizer.ttype);
            }//switch end
        }I've also tried this and i get output, but the the concat command has not any effect; the characters are printed one on each line.
while(tokenizer.nextToken()!= StreamTokenizer.TT_EOF)
            switch(tokenizer.ttype)
                case StreamTokenizer.TT_EOL:               
                break;
                case StreamTokenizer.TT_NUMBER:
                s.concat(Double.toString(tokenizer.nval));
                break;
                case StreamTokenizer.TT_WORD:
                s.concat(tokenizer.sval); // Already a String
                break;
                default: // single character in ttype
                s = String.valueOf((char)tokenizer.ttype);
            }//switch end
            System.out.print(s);
        }Why? Is there any secret inside "switch"?

Answer 1

I've also tried this and i get output, but the the concat command has
not any effect; the characters are printed one on each line.Strings are immutable, so instead of this:s.concat(Double.toString(tokenizer.nval));do this:s= s.concat(Double.toString(tokenizer.nval));(the same applies to the other 'concat' statements).
kind regards,
Jos