In the following code there are three patters used, one of them is the Singleton, please name the other two patterns and for each pattern mention the name of class and its role in that pattern

Foo { public public interface B{ public class Bar public interface interface A{ public void implements Foo { b1(Foo f); public void public B public void foo1(){ foo1(); a1(); } public void b2(); } System.out.println(""); } } } public class DA implements A{ public class EB implements B { private static DA variable1 = new private ArrayList list1 = new DA(); ArrayList(); private DA() { public void b1(Foo f) { } list1.add(f); private static DA deadbeef1() { } public void b2() { return variable1; for (Foo f: list1) { } public B a1() { f.foo1(); return new EB(); } } } } }