Overloading When Combining Widening and Boxing : Boxing Unboxing « Utility Classes « SCJP

1. SCJP
2. Utility Classes
3. Boxing Unboxing

class MainClass {
  static void go(Long x) { System.out.println("Long"); }

  public static void main(String [] args) {
    byte b = 5;
    go(b);           // must widen then box - illegal
  }
}

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	The method go(Long) in the type MainClass is not applicable for the arguments (byte)

	at MainClass.main(MainClass.java:6)