public static void checkArgument(boolean expression,Object errorMessage){
  if (ExoPlayerLibraryInfo.ASSERTIONS_ENABLED && !expression) {
    throw new IllegalArgumentException(String.valueOf(errorMessage));
  }
}

public static void checkArgument ( boolean expression , Object errorMessage ) { if ( ExoPlayerLibraryInfo . ASSERTIONS_ENABLED && ! expression ) { throw new IllegalArgumentException ( String . valueOf ( errorMessage ) ) ; } }
ensures the truth of an expression involving one or more arguments passed to the calling method .
