Abstract Singleton Cache Factory

AwesomeService.java

package hurrdurrtest;

public class AwesomeService extends ServiceBase {
    private String context;

    @Override
    public void setContext(String ctx) {
        System.out.println("Yo, the context is " + ctx);
        context = ctx;
    }

    public AwesomeService() {
        System.out.println("AwesomeService instantiated.");
    }

    void shoutThineContext() {
        System.out.println(context.toUpperCase() + " IS MY CONTEXT.");
    }
}

Expected output

AwesomeService instantiated.
Yo, the context is derpy hooves
DERPY HOOVES IS MY CONTEXT.
Yo, the context is herpy doves
HERPY DOVES IS MY CONTEXT.
Pretty sure no new instance was created. All good

HurrDurrTest.java

/*
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package hurrdurrtest;

public class HurrDurrTest {

    public static void main(String[] args) {
        try {
            AwesomeService srv1 = null;
            AwesomeService srv2 = null;
            srv1 = ServiceManager.get(AwesomeService.class, "derpy hooves");
            srv1.shoutThineContext();
            srv2 = ServiceManager.get(AwesomeService.class, "herpy doves");
            srv2.shoutThineContext();
            if(srv1 == srv2) System.out.println("Pretty sure no new instance was created. All good");
            
        } catch (InstantiationException ex) {
        } catch (IllegalAccessException ex) {
        }
    }
}

ServiceBase.java

package hurrdurrtest;

public abstract class ServiceBase {
    public abstract void setContext(String ctx);
}

ServiceManager.java

package hurrdurrtest;
import java.util.HashMap;

public class ServiceManager {
    private static HashMap<Class, ServiceBase> cache = new HashMap<Class, ServiceBase>();
    public static <T extends ServiceBase> T get(Class<T> klass, String ctx) throws InstantiationException, IllegalAccessException {
        T inst = null;
        if(cache.containsKey(klass)) {
            inst = (T)cache.get(klass);
        } else {
            cache.put((Class)klass, inst = (T)klass.newInstance());
        }
        inst.setContext(ctx);
        return inst;
    }
}