"OVERLOAD":
1, the OVERLOAD method is named, the number, the number, the order is at least one different;
2, can't overload only the method names that return values;
3, OverLoad exists in the parent class and subclasses, in the same kind.
"Override"
1. When OVERRIDE, the method name, parameter, and return value are the same;
2. Subclass methods cannot narrow the access rights of the parent method;
3. Submatory methods cannot throw more abnormalities than parent class methods (but the sub-class method can not throw an abnormality);
4, Override exists between the parent class and subclass.
