Алексей Черемисин

package jtests;
import java.lang.System;

public class MyTest {

	class A {
		String  a () {
			return("from A:a");
		}
		String b() {		
			return("from A:b - " + a());
		}
		
	}
	class B extends A {
		@Override String b() {
			return ("from B:b - " + super.b());
		}
	}
	
	public static void main(String[] args) {
		MyTest m = new MyTest();
				
		System.out.println("A");
		A a =  m.new A(); // Используем A
		System.out.println(a.getClass().getName() + " * " + a.b());
		
		System.out.println("B");
		B b =  m.new B(); // Используем B
		System.out.println(b.getClass().getName() + " * " + b.b());
		
		System.out.println("B -> A");		
		A ab = (A) m.new B(); // Используем B как A
		System.out.println(ab.getClass().getName() + " * " + ab.b());
	}
}

A
jtests.MyTest$A * from A:b - from A:a
B
jtests.MyTest$B * from B:b - from A:b - from A:a
B -> A
jtests.MyTest$B * from B:b - from A:b - from A:a

package my.com;

import java.util.HashMap;
import java.util.Map;

public class MyJob {
	class Context {
		private String astring;

		public Context(String string){
			this.setAstring(string);
			// set properties
		}

		public String getAstring() {
			return astring;
		}

		public void setAstring(String astring) {
			this.astring = astring;
		}
	}
	
	interface Worker {
		public int doWork(Context c);
	}

	class MultiChoose implements Worker {

		@Override
		public int doWork(Context c) {
			c.getAstring();
			System.out.println(c.getAstring() +" MultiChoose");
			c.setAstring("Новая фигня");
			return 0;
		}
		
	}

	class Choose implements Worker {

		@Override
		public int doWork(Context c) {
			System.out.println(c.getAstring() +" Choose");
			return 0;
		}
		
	}
	class AnotherString implements Worker {

		@Override
		public int doWork(Context c) {
			System.out.println(c.getAstring() + " AnotherString");
			return 0;
		}
		
	}

	class Nothing implements Worker {

		@Override
		public int doWork(Context c) {
			System.out.println("Nothing");
			return 1;
		}
		
	}
	public static void main(String[] args) {
		MyJob job = new MyJob();
		Map<String, Worker> cases = new HashMap<String, Worker>();
		cases.put("Выбор", job.new Choose());
		cases.put("МультиВыбор", job.new MultiChoose());
		cases.put("yetanotherSubString", job.new AnotherString());
		
		
		String[] keys_for_test = {"Выбор","МультиВыбор","yetanotherSubString","WrongKey"};
		Context content = job.new Context("Всякая фигня");

		for (String key:keys_for_test) {
			Worker worker = cases.getOrDefault(key, job.new Nothing());
			worker.doWork(content);
		}

	}

}

Всякая фигня Choose
Всякая фигня MultiChoose
Новая фигня AnotherString
Nothing