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What is a lazy initialization in singleton?
Lazy initialization: In this method, object is created only if it is needed. This may prevent resource wastage. An implementation of getInstance() method is required which return the instance. There is a null check that if object is not created then create, otherwise return previously created.
What is double locking in singleton?
In double-checked locking, code checks for an existing instance of Singleton class twice with and without locking to make sure that only one instance of singleton gets created.
Why do we need double-checked locking?
The double checked pattern is used to avoid obtaining the lock every time the code is executed. If the call are not happening together then the first condition will fail and the code execution will not execute the locking thus saving resources.
What is difference between static and Singleton?
A singleton allows access to a single created instance – that instance (or rather, a reference to that instance) can be passed as a parameter to other methods, and treated as a normal object. A static class allows only static methods. Singleton objects are stored in Heap, but static objects are stored in stack.
Why do we use Singleton class in C#?
Singleton Class allow for single allocations and instances of data. It has normal methods and you can call it using an instance. To prevent multiple instances of the class, the private constructor is used.
When do we initialize a singleton in Modernes?
I use in the reference implementation the so-called Meyers Singleton. The elegance of this implementation is that the singleton object instance in line 11 is a static variable with a block scope. Therefore, instance will exactly be initialized, when the static method getInstance (line 10 – 14) will be executed the first time.
What is the Singleton lock pattern in C #?
Performing the lock is terribly expensive when compared to the simple pointer check instance != null. The pattern you see here is called double-checked locking. Its purpose is to avoid the expensive lock operation which is only going to be needed once (when the singleton is first accessed).
How to solve the problem with lazy initialization and Singleton?
One way to solve the problem with Lazy initialization and singleton in a multi threaded program is to declare the getInstance () or getResource () method as synchronized.
Is it better to use a static singleton or a volatile Singleton?
(Incidentally, if you can possibly just use private static volatile Singleton instance = new Singleton () or if you can possibly just not use singletons but use a static class instead, both are better in regards to these concerns). The reason is performance.