[JAVA-621] Added missing code

* https://www.baeldung.com/java-type-erasure introduction code

* https://www.baeldung.com/java-interfaces Electronic interface and Computer class

* https://www.baeldung.com/java-abstract-class BoardGame and Checkers classes

* https://www.baeldung.com/java-hashcode different ways of implementing hashCode

* https://www.baeldung.com/java-inheritance-composition ComputerBuilder and StandardComputerBuilder classes

* https://www.baeldung.com/java-equals-hashcode-contracts Renamed method to match article

* https://www.baeldung.com/java-static Renamed class to match article

* https://www.baeldung.com/java-nested-classes Renamed class to match article

core-java-modules/core-java-lang-oop-generics/src/main/java/com/baeldung/typeerasure/Example.java

@@ -0,0 +1,13 @@
+package com.baeldung.typeerasure;
+
+public class Example {
+
+    public static  <E> boolean containsElement(E [] elements, E element){
+        for (E e : elements){
+            if(e.equals(element)){
+                return true;
+            }
+        }
+        return false;
+    }
+}