diff --git a/adapter/src/main/java/com/iluwatar/adapter/App.java b/adapter/src/main/java/com/iluwatar/adapter/App.java
index a3bf5b14b..570cc8272 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/App.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/App.java
@@ -24,37 +24,44 @@
 package com.iluwatar.adapter;
 
 /**
- * An adapter helps two incompatible interfaces to work together. This is the real world definition
- * for an adapter. Interfaces may be incompatible but the inner functionality should suit the need.
- * The Adapter design pattern allows otherwise incompatible classes to work together by converting
- * the interface of one class into an interface expected by the clients.
+ * An adapter helps two incompatible interfaces to work together. This is the
+ * real world definition for an adapter. Interfaces may be incompatible but
+ * the inner functionality should suit the need. The Adapter design pattern
+ * allows otherwise incompatible classes to work together by converting the
+ * interface of one class into an interface expected by the clients.
  *
  * <p>
- * There are two variations of the Adapter pattern: The class adapter implements the adaptee's
- * interface whereas the object adapter uses composition to contain the adaptee in the adapter
- * object. This example uses the object adapter approach.
+ * There are two variations of the Adapter pattern: The class adapter
+ * implements the adaptee's interface whereas the object adapter uses
+ * composition to contain the adaptee in the adapter object. This example uses
+ * the object adapter approach.
  *
  * <p>
- * The Adapter ({@link FishingBoatAdapter}) converts the interface of the adaptee class (
- * {@link FishingBoat}) into a suitable one expected by the client ( {@link RowingBoat} ).
+ * The Adapter ({@link FishingBoatAdapter}) converts the interface of the
+ * adaptee class ({@link FishingBoat}) into a suitable one expected by the
+ * client ({@link RowingBoat}).
  *
  * <p>
  * The story of this implementation is this. <br>
- * Pirates are coming! we need a {@link RowingBoat} to flee! We have a {@link FishingBoat} and our
- * captain. We have no time to make up a new ship! we need to reuse this {@link FishingBoat}. The
- * captain needs a rowing boat which he can operate. The spec is in {@link RowingBoat}. We will
- * use the Adapter pattern to reuse {@link FishingBoat}.
+ * Pirates are coming! we need a {@link RowingBoat} to flee! We have a
+ * {@link FishingBoat} and our captain. We have no time to make up a new ship!
+ * we need to reuse this {@link FishingBoat}. The captain needs a rowing boat
+ * which he can operate. The spec is in {@link RowingBoat}. We will use the
+ * Adapter pattern to reuse {@link FishingBoat}.
  *
  */
-public class App {
+public final class App {
+
+  private App() { }
 
   /**
    * Program entry point.
    *
    * @param args command line args
    */
-  public static void main(String[] args) {
-    // The captain can only operate rowing boats but with adapter he is able to use fishing boats as well
+  public static void main(final String[] args) {
+    // The captain can only operate rowing boats but with adapter he is able to
+    // use fishing boats as well
     var captain = new Captain(new FishingBoatAdapter());
     captain.row();
   }
diff --git a/adapter/src/main/java/com/iluwatar/adapter/Captain.java b/adapter/src/main/java/com/iluwatar/adapter/Captain.java
index fbf0be6ca..1eb3aaa1a 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/Captain.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/Captain.java
@@ -27,21 +27,21 @@ package com.iluwatar.adapter;
  * The Captain uses {@link RowingBoat} to sail. <br>
  * This is the client in the pattern.
  */
-public class Captain {
+public final class Captain {
 
   private RowingBoat rowingBoat;
 
-  public Captain() {}
+  public Captain() { }
 
-  public Captain(RowingBoat rowingBoat) {
-    this.rowingBoat = rowingBoat;
+  public Captain(final RowingBoat boat) {
+    this.rowingBoat = boat;
   }
 
-  public void setRowingBoat(RowingBoat rowingBoat) {
-    this.rowingBoat = rowingBoat;
+  void setRowingBoat(final RowingBoat boat) {
+    this.rowingBoat = boat;
   }
 
-  public void row() {
+  void row() {
     rowingBoat.row();
   }
 
diff --git a/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java b/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
index 6c2daae3d..1dbf5eed3 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
@@ -24,7 +24,8 @@
 package com.iluwatar.adapter;
 
 import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+
+import static org.slf4j.LoggerFactory.getLogger;
 
 /**
  *
@@ -32,11 +33,11 @@ import org.slf4j.LoggerFactory;
  * Fishing boat moves by sailing.
  *
  */
-public class FishingBoat {
+final class FishingBoat {
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
+  private static final Logger LOGGER = getLogger(FishingBoat.class);
 
-  public void sail() {
+  void sail() {
     LOGGER.info("The fishing boat is sailing");
   }
 
diff --git a/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java b/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
index 7dda379c9..7aaacd3e5 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
@@ -25,8 +25,8 @@ package com.iluwatar.adapter;
 
 /**
  *
- * Adapter class. Adapts the interface of the device ({@link FishingBoat}) into {@link RowingBoat}
- * interface expected by the client ({@link Captain}).
+ * Adapter class. Adapts the interface of the device ({@link FishingBoat})
+ * into {@link RowingBoat} interface expected by the client ({@link Captain}).
  *
  */
 public class FishingBoatAdapter implements RowingBoat {
@@ -37,8 +37,7 @@ public class FishingBoatAdapter implements RowingBoat {
     boat = new FishingBoat();
   }
 
-  @Override
-  public void row() {
+  public final void row() {
     boat.sail();
   }
 }
diff --git a/adapter/src/main/java/com/iluwatar/adapter/package-info.java b/adapter/src/main/java/com/iluwatar/adapter/package-info.java
new file mode 100644
index 000000000..eb7e442f9
--- /dev/null
+++ b/adapter/src/main/java/com/iluwatar/adapter/package-info.java
@@ -0,0 +1 @@
+package com.iluwatar.adapter;