Perhaps like this:

1. void draw() {
2. }
3. void keyPressed() {
4.   switch(keyCode) {
5.   case UP:
6.     println("up");
7.     break;
8.   case DOWN:
9.     println("down");
10.     break;
11.   case RIGHT:
12.     println("right");
13.     break;
14.   case LEFT:
15.     println("left");
16.     break;
17.   }
18. }

life is so easy

I tested it with '1' '2' and the arrows LEFT etc. and that worked.
Only later i found out that 's' didn't work for example.

this works:

1. void draw() {
   }
   
   void keyPressed() {
     switch(keyCode) {
     case UP:
       println("up");
       break;
     }
   
     switch(key) {
     case 's':
       println("s");
       break;
     }
   }
   
   

Ya, not sure if it would help, but you could also wrap the select statements in an if statement.  Might reduce the cycles...

1. if (key != CODED) {
2.   switch(key) {
3.   case 's':
4.     println("s");
5.     break;
6.   }
7. } else {
8.   switch(keyCode) {
9.   case UP:
10.     println("up");
11.     break;
12.   }
13. }