Thanks to share your DI framework idea with me, I did not know about that.

public class Singleton {
private static final Singleton INSTANCE = new Singleton();

private Singleton() { }

public static Singleton getInstance() {
return INSTANCE;
}
}

this work fine with java, but don’t have any idea about .NET. pretending it should work.

btw, as in java, we are not extensively using singleton pattern rather we all are using dependency injection pattern.

let’s say the above class singleton won’t keep INSTANCE variable any more.

rather our dependency injection framework will manage it’s instance and will inject through setter method of our required class.

let’s say.

class ServiceA {
// do bla bla bla
}

class ServiceAConsumer {
private final ServiceA mServiceA;

public ServiceAConsumer(final ServiceA pServiceA) {
mServiceA = pServiceA;
}

// do my job with ServiceA instance
// ie.
}

without DI framework we would do the following code –
class ServiceAConsumer {
private final ServiceA mServiceA;

public ServiceAConsumer() {
mServiceA = ServiceA.getInstance();
}

// do my job with ServiceA instance
// ie.
}

as you see we are binding our dependency in implementation level, let’s say ServiceA is an interface and ServiceAImpl is the concrete implementation. so you would write ServiceAImpl.getInstance(). when you have many services like this, it will become hard to maintain. thats why we are giving more priority on DI.

i think you will dig more about this area.
btw nice write up. keep up your good works.

public class Singleton
{
private static Singleton UniqueInstance;
private static Object syncLock = new Object();

private Singleton()
{
}

public static Singleton GetInstance()
{
lock(syncLock)
{
if (UniqueInstance == null)
{
UniqueInstance = new Singleton();
}
}
return UniqueInstance;
}
}