Added new code snippets to OptionalTest to further demo filter API (#881)

* made changes to java reflection

* removed redundant method makeSound in Animal abstract class

* added project for play-framework article

* added project for regex

* changed regex project from own model to core-java

* added project for routing in play

* made changes to regex project

* refactored code for REST API with Play project

* refactored student store indexing to zero base

* added unit tests, removed bad names

* added NIO Selector project under core-java module

* requested changes made

* added project for nio2

* standardized exception based tests

* fixed exception based tests

* removed redundant files

* added network interface project

* used UUID other than timestamps

* fixed network interface tests

* removed filetest change

* made changes to NIO2 FileTest names

* added project for asyncronous channel apis

* added project for NIO2 advanced filesystems APIS

* merge conflicts

* merged changes to asyncfiletest with future get API

* removed while loops from async client and server

* added project for java8 optional

* fixed merge conflicts in spring-core

* fixed optional

* fixed optional

* fixed asyncechotest

* shifted optional to own package

* made additional tests to demo filter API

core-java/src/main/java/com/baeldung/optional/Modem.java

@@ -0,0 +1,13 @@
+package com.baeldung.optional;
+
+public class Modem {
+    private Double price;
+
+    public Modem(Double price) {
+        this.price = price;
+    }
+
+    public Double getPrice() {
+        return price;
+    }
+}

core-java/src/main/java/com/baeldung/optional/Person.java

@@ -1,4 +1,4 @@
-package com.baeldung.java_8_features;
+package com.baeldung.optional;
 
 import java.util.Optional;