WIDENING BOXING AND VARARGS 7 RULES

WIDENING BOXING AND VARARGS 7 RULES

WBV

1. Primitive Widening > Boxing > Varargs.

2. Widening and Boxing (WB) not allowed.

3. Boxing and Widening (BW) allowed.

4. While overloading Widening + vararg and boxing + vararg are mutually exclusive of each other.

5. Widening between wrapper classes not allowed

6. Widening+varArgs & Boxing+varargs are individuall
y allowed (but not allowed in overloaded version of method)

7. Boxing+Widening is preferred over Boxing+Varargs.

foo(5);

foo(Integer i)  and foo(long l)     // long (by Rule 1)

   //Explanation:

   //int to Integer - boxing

   //int to long - widening

   // Rule 1: widening > boxing

    

foo(int...i) and foo(Integer i)   // Integer (by Rule 1)

   //Explanation:

   //int to int... - varargs

   //int to Integer - boxing

   // Rule 1: boxing > varargs

foo(long...l)   and foo(Integer i)   //  Integer (Rule 1)

   //Explanation:

   //int to long... - varargs

   //int to Integer - boxing

   // Rule 1: boxing > varargs

foo(Object o)   and foo(int...i)     // Object o (Rule 1)

   //Explanation:

   //int to int... - varargs

   //int to Object - boxing

   // Rule 1: boxing > varargs

    

foo(Object o)   and foo(long l)     // long l (Rule 1)

   //Explanation:

   //int to long - widening

   //int to Object - boxing

   // Rule 1: widening > boxing

foo(Object o)   and foo(Integer... l)   // Object o (Rule 1)

   //Explanation:

   //int to Integer... - boxing + varargs

   //int to Object - boxing

   // Rule 1: boxing > varargs

foo(Long l) and foo(int...i)     // int...i (Rule 2 )

   //Explanation:

   //int to Long - widening (to long) + boxing (to Long)

   //int to int... - varargs

   // Rule 2: widening + boxing is not allowed

foo(Long l) and foo(Integer...i) // Integer...i(Rule 2)

   //Explanation:

   //int to Long - widening (to long) + boxing (to Long)

   //int to Integer... - boxing + varargs

   // Rule 2: widening + boxing is not allowed

foo(Object o)   and foo(Long l)     // Object o (Rule 2)

   //Explanation:

   //int to Long - widening (to long) + boxing (to Long)

   //int to Object - boxing

   // Rule 2: widening + boxing is not allowed

    

foo(long...l)   and foo(Integer...i) //  ambiguous (Rule 4)

   //Explanation:

   //int to long... - widening + varargs

   //int to Integer... - boxing + varargs

   // Rule 4: widening + vararg and boxing + vararg are mutually exclusive of each other.