Singleton via enum way is lazy initialized?

Question

This is a very wide-spread enum singleton code:

public enum enumClazz{
   INSTANCE
   enumClazz(){
     //do something
   }
}

and a bunch o

Answer 1

The third point with bold style clarify that if the field is 'static final', the initialzation of the field is happened at complie-time

Not exactly - it only applies to "static fields that are final and initialized by a compile-time constant expression":

static final String = "abc"; //compile time constant
static final Object = new Object(); //initialised at runtime

In your case, the singleton will be initialised when the enum class is loaded, i.e. the first time enumClazz is referenced in your code.

So it is effectively lazy, unless of course you have a statement somewhere else in your code that uses the enum.