Exam 1z0-809 topic 1 question 114 discussion

C,D, not B otherwise could keep calling that public method and instantiate multiple times

Band D. it needs the public method not public static . public static method always returns a copy of it.

C and D are correct since we need static method to return instance of singleton and private constructor so that it is not possible to create multiple instances.

Considering the standard Singleton implementation (i.e. the Bill Pugh implementation) : public class BillPughSingleton { private BillPughSingleton(){} private static class SingletonHelper{ private static final BillPughSingleton INSTANCE = new BillPughSingleton(); } public static BillPughSingleton getInstance(){ return SingletonHelper.INSTANCE; } } We can conclude that answer is CD

anser is C D

Answer : CD

public class SingletonGreed { private static SingletonGreed instance = new SingletonGreed(); private SingletonGreed(){} public static SingletonGreed getInstance () { return instance; } }

it is BD because constructor has to be private to prevent instantiation and also there must be a method to check if there is already an object of it to provide otherwise create a new one.

D E~~~!!!

C,D checked.