BAEL-4464 : how to implement LRU-Cache in java codes added (#11036)

* BAEL-4464 : how to implement LRU-Cache in java codes added

* BAEL-4464 : how to implement LRU-Cache in java codes added - package named fixed

* BAEL-4464 : how to implement LRU-Cache in java codes added - package named changed

* BAEL-4464 : how to implement LRU-Cache in java codes added - unitTest fixed

data-structures/src/main/java/com/baeldung/lrucache/Cache.java

@@ -0,0 +1,15 @@
+package com.baeldung.lrucache;
+
+import java.util.Optional;
+
+public interface Cache<K, V> {
+    boolean put(K key, V value);
+
+    Optional<V> get(K key);
+
+    int size();
+
+    boolean isEmpty();
+
+    void clear();
+}