Added MapDemo

Author: dPetrotos

Diff for: java-path-core-collections/src/main/java/gr/codelearn/MapDemo.java

@@ -0,0 +1,65 @@
+package gr.codelearn;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class MapDemo {
+    public static void main(String[] args) {
+//        createMap();
+        otherMapActions();
+    }
+
+    private static void createMap() {
+        Map<String, String> map = Map.of();
+
+        Map<String, String> map2 = Map.of("key1", "value1", "key2", "value2");
+        System.out.println(map2);
+
+        Map<String, String> map3 = Map.ofEntries(Map.entry("key1", "value1"), Map.entry("key2", "value2"));
+        System.out.println(map3);
+
+        Map<String, String> map4 = new HashMap<>();
+        map4.put("Android", "Mobile");
+        map4.put("Eclipse IDE", "Java");
+        map4.put("Intellij IDEA", "Java");
+        map4.put("Git", "Version control system");
+
+        map4.put("Git", "A new value");
+
+        System.out.println(map4);
+    }
+
+    private static void otherMapActions() {
+        Map<String, String> map = new HashMap<>();
+        map.put("Android", "Mobile");
+        map.put("Eclipse IDE", "Java");
+        map.put("Intellij IDEA", "Java");
+        map.put("Git", "Version control system");
+
+//        System.out.println(map.get("Eclipse IDE"));
+
+        for (Map.Entry<String, String> mapEntry : map.entrySet()) {
+            System.out.println(mapEntry);
+        }
+
+        System.out.println("\nPrinting the keys:");
+        for (String key : map.keySet()) {
+            System.out.println(key);
+        }
+
+        System.out.println("\nPrinting the values:");
+        for (String value : map.values()) {
+            System.out.println(value);
+        }
+
+        System.out.println("\nDoes the map contain a value for Android:");
+        System.out.println(map.containsKey("Android"));
+        System.out.println(map.containsValue("Mobile"));
+
+        System.out.println(map.getOrDefault("Sth", "Not found"));
+
+        map.clear();
+
+        System.out.println(map);
+    }
+}