Add README descriptions 28! (#7917)

core-groovy-collections/README.md

@@ -1,4 +1,6 @@
-# Groovy
+## Core Groovy Collections
+
+This module contains articles about Groovy core collections
 
 ## Relevant articles:
 

core-java-modules/core-java-10/README.md

@@ -1,3 +1,6 @@
+## Core Java 10
+
+This module contains articles about Java 10 core features
 
 ### Relevant Articles: 
 

core-java-modules/core-java-11/README.md

@@ -1,3 +1,7 @@
+## Core Java 11
+
+This module contains articles about Java 11 core features
+
 ### Relevant articles
 
 - [Java 11 Single File Source Code](https://www.baeldung.com/java-single-file-source-code)

core-java-modules/core-java-8-2/README.md

@@ -1,6 +1,6 @@
-=========
+## Core Java 8 (part 2)
 
-## Core Java 8 Cookbooks and Examples (part 2)
+This module contains articles about Java 8 core features
 
 ### Relevant Articles: 
 - [Anonymous Classes in Java](http://www.baeldung.com/)
@@ -8,3 +8,4 @@
 - [Run a Java Application from the Command Line](https://www.baeldung.com/java-run-jar-with-arguments)
 - [Java 8 Stream skip() vs limit()](https://www.baeldung.com/java-stream-skip-vs-limit)
 - [Guide to Java BiFunction Interface](https://www.baeldung.com/java-bifunction-interface)
+- [[<-- Prev]](/core-java-modules/core-java-8)

core-java-modules/core-java-8/README.md

@@ -1,6 +1,6 @@
-=========
+## Core Java 8
 
-## Core Java 8 Cookbooks and Examples
+This module contains articles about Java 8 core features
 
 ### Relevant Articles: 
 - [New Features in Java 8](https://www.baeldung.com/java-8-new-features)
@@ -12,3 +12,4 @@
 - [Finding Min/Max in an Array with Java](https://www.baeldung.com/java-array-min-max)
 - [Internationalization and Localization in Java 8](https://www.baeldung.com/java-8-localization)
 - [Generalized Target-Type Inference in Java](https://www.baeldung.com/java-generalized-target-type-inference)
+- [[More -->]](/core-java-modules/core-java-8-2)

core-java-modules/core-java-9/README.md

@@ -1,8 +1,6 @@
-=========
+## Core Java 9
 
-## Core Java 9  Examples
-
-[Java 9 New Features](http://www.baeldung.com/new-java-9)
+This module contains articles about Java 9 core features
 
 ### Relevant Articles:
 

core-java-modules/core-java-arrays-2/README.md

@@ -1,3 +1,7 @@
+## Core Java Arrays (Part 2)
+
+This module contains articles about Java arrays
+
 ## Relevant Articles
 
 - [Extending an Array’s Length](https://www.baeldung.com/java-array-add-element-at-the-end)
@@ -8,3 +12,4 @@
 - [Intersection Between two Integer Arrays](https://www.baeldung.com/java-array-intersection)
 - [Removing an Element from an Array in Java](https://www.baeldung.com/java-array-remove-element)
 - [Removing the First Element of an Array](https://www.baeldung.com/java-array-remove-first-element)
+- [[<-- Prev]](/core-java-modules/core-java-arrays)

core-java-modules/core-java-arrays/README.md

@@ -1,6 +1,6 @@
-=========
+## Core Java Arrays
 
-## Core Java Arrays Cookbooks and Examples
+This module contains articles about Java arrays
 
 ### Relevant Articles: 
 - [How to Copy an Array in Java](https://www.baeldung.com/java-array-copy)
@@ -14,3 +14,4 @@
 - [How to Reverse an Array in Java](http://www.baeldung.com/java-invert-array)
 - [Sorting Arrays in Java](https://www.baeldung.com/java-sorting-arrays)
 - [Checking If an Array Is Sorted in Java](https://www.baeldung.com/java-check-sorted-array)
+- [[More -->]](/core-java-modules/core-java-arrays-2)

core-java-modules/core-java-collections/README.md

@@ -1,6 +1,6 @@
-=========
+## Core Java Collections
 
-## Core Java Collections Cookbooks and Examples
+This module contains articles about Java collections
 
 ### Relevant Articles: 
 - [Collect a Java Stream to an Immutable Collection](https://www.baeldung.com/java-stream-immutable-collection)
@@ -13,3 +13,4 @@
 - [Defining a Char Stack in Java](https://www.baeldung.com/java-char-stack)
 - [Guide to the Java Queue Interface](https://www.baeldung.com/java-queue)
 - [An Introduction to Synchronized Java Collections](https://www.baeldung.com/java-synchronized-collections)
+- [[More -->]](/core-java-modules/core-java-collections-2)

core-java-modules/core-java-os/README.md

@@ -1,10 +1,11 @@
-=========
+## Core Java OS
 
-This module uses Java 9, so make sure to have the JDK 9 installed to run it.
+This module contains articles about working with the operating system (OS) in Java
 
-## 
 ### Relevant Articles: 
 - [Java 9 Process API Improvements](http://www.baeldung.com/java-9-process-api)
 - [Guide to java.lang.Process API](https://www.baeldung.com/java-process-api)
 - [Guide to java.lang.ProcessBuilder API](https://www.baeldung.com/java-lang-processbuilder-api)
 - [Get the Current Working Directory in Java](https://www.baeldung.com/java-current-directory)
+
+This module uses Java 9, so make sure to have the JDK 9 installed to run it.