java - Using Singleton Design with Inheritance in a multithreaded Application -

i having application code written this

public interface superclass{ //....to methods }  public class baseclass1 implements superclass{ //....to methods }  public class baseclass2 implements superclass{ //....to methods } 

now in application 1 object can instantiated superclass reference, i.e synchronized singleton.

now, can include

public static synchronized  superclass getinstance(){    //initialise } 

in of base classes, cannot include declaration in superclass interface due cannot instance of base class using reference of super class. e.g. want this(its vague example)

baseclass1 bc1 = baseclass1.getinstance();  superclass sc = bc1.getinstance(); 

now somewhere later in code

bc1=sc.getinstance(); 

how can achieved?

note: several threads accessing these objects hence synchronisation mandatory

instead of using singletons why dont use dependency injection eg: google guice.

guice create instance of super class , can access via injector.getinstance() method.