added more example

core-java/src/main/java/com/baeldung/generics/Building.java

@@ -0,0 +1,5 @@
+
+public class Building {
+	public void paint() {
+	}
+}

core-java/src/main/java/com/baeldung/generics/Generics.java

@@ -1,4 +1,5 @@
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class Generics {
@@ -6,19 +7,24 @@ public class Generics {
 	// definition of a generic method
 	public static <T> List<T> fromArrayToList(T[] a) {
 		List<T> list = new ArrayList<>();
-		for (T t : a) {
-			list.add(t);
-		}
+		Arrays.stream(a).forEach(list::add);
 		return list;
 	}
 
 	// example of a generic method that has Number as an upper bound for T
 	public static <T extends Number> List<T> fromArrayToListWithUpperBound(T[] a) {
 		List<T> list = new ArrayList<>();
-		for (T t : a) {
-			list.add(t);
-		}
+		Arrays.stream(a).forEach(list::add);
 		return list;
 	}
 
-}
+	// example of a generic method with a wild card, this method can be used
+	// with a list of any subtype of Building
+	public static boolean paintAllBuildings(List<? extends Building> buildings) {
+		for (Building building : buildings) {
+			building.paint();
+		}
+		return true;
+	}
+
+}

core-java/src/main/java/com/baeldung/generics/SubBuilding.java

@@ -0,0 +1,4 @@
+
+public class SubBuilding extends Building {
+
+}