州

public interface 州 {
    public void doAction(Context context);
}

public class Start州 implements 州 {
    private Context context;
    public Start州(){}
    @Override
    public void doAction(Context context){
        this.context = context;
        this.context.set州(this);
        System.out.println("Player is in Start州");
    }

    public String toString(){
        return "Start 州";
    }
}

public class End州 implements 州 {
    private Context context;
    public End州(){}
    @Override
    public void doAction(Context context){
        this.context = context;
        this.context.set州(this);
        System.out.println("Player is in End州");
    }

    public String toString(){
        return "End 州";
    } 
}

public class Main {
    public static void main(String args[]){
        Context context = new Context();
        州 state = new Start州();
        state.doAction(context);
        //current state
        System.out.println(context.get州().toString());

        州 state2 = new End州();
        state2.doAction(context);
        //new 州
        System.out.println(context.get州().toString());
    }
}

Player is in Start州
Start 州
Player is in End州
End 州