Simulation for repeatedly taking gloves until a matching pair is found
Make the glove types an enum

public static enum GLOVE {
  RED_LEFT, RED_RIGHT,
  YELLOW_LEFT, YELLOW_RIGHT, 
  GREEN_LEFT, GREEN_RIGHT
}


this has several benefits:


with the current String solution, you can have a typo and you will not detect this until run time.  With an enum, the compiler checks values for you
the matchList.contains... if statement can be replaced by iteration on enum values 
checking equality on enum values is faster then String comparison


if you want an even better solution, you should make a Glove class with two attributes, color of type enum and hand of type enum.  then, implement equals() and hash() methods so you can put Glove instances in various Collections. The benefit if this solution is that it allows for future modification to Glove specifications (like, adding colors, adding material attribute, etc)