Java uses static factory instead of constructor use method and advantage and disadvantage _java

1. Form

Copy Code code as follows:

public static Boolean valueof (Boolean b) {
Return b? Boolean.TRUE:Boolean.FALSE;
}

2. Advantages:

can have a name
You don't have to create a new object, you can return an existing object
An object that can return a subclass type (example: java.util.Collections)
Make parameterized code shorter (example: New Hashmap<string,list<string>> () to Hashmap.newinstance ())

3. Disadvantage: Cannot subclass, not be recognized by IDE tools.

4. Common name: valueof/of; GetInstance (Singleton); newinstance; GetType (used in different classes); NewType