Code for Map (#909)

* 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

* added code for Map

core-java/src/main/java/com/baeldung/java/map/MyKey.java

@@ -0,0 +1,59 @@
+package com.baeldung.java.map;
+
+public class MyKey {
+    private String name;
+    private int id;
+
+    public MyKey(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    @Override
+    public int hashCode() {
+        System.out.println("Calling hashCode()");
+        return id;
+    }
+
+    @Override
+    public String toString() {
+        return "MyKey [name=" + name + ", id=" + id + "]";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        System.out.println("Calling equals() for key: " + obj);
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        MyKey other = (MyKey) obj;
+        if (id != other.id)
+            return false;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        return true;
+    }
+
+}

core-java/src/main/java/com/baeldung/java/map/MyLinkedHashMap.java

@@ -0,0 +1,25 @@
+package com.baeldung.java.map;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class MyLinkedHashMap<K, V> extends LinkedHashMap<K, V> {
+
+    /**
+     * 
+     */
+    private static final long serialVersionUID = 1L;
+    private static final int MAX_ENTRIES = 5;
+    
+
+    public MyLinkedHashMap(int initialCapacity, float loadFactor, boolean accessOrder) {
+        super(initialCapacity, loadFactor, accessOrder);
+    }
+
+
+    @Override
+    protected boolean removeEldestEntry(Map.Entry eldest) {
+        return size() > MAX_ENTRIES;
+    }
+
+}