diff --git a/caching/src/main/java/com/iluwatar/caching/AppManager.java b/caching/src/main/java/com/iluwatar/caching/AppManager.java
index 925320cd682905be2857b87df1cfbcd1e99a9742..519226640edf83bb7cad1bb4817e1312b5a3e7ed 100644
--- a/caching/src/main/java/com/iluwatar/caching/AppManager.java
+++ b/caching/src/main/java/com/iluwatar/caching/AppManager.java
@@ -15,6 +15,9 @@ public class AppManager {
 
   private static CachingPolicy cachingPolicy;
 
+  private AppManager() {
+  }
+
   /**
    *
    * Developer/Tester is able to choose whether the application should use MongoDB as its underlying
diff --git a/caching/src/main/java/com/iluwatar/caching/CacheStore.java b/caching/src/main/java/com/iluwatar/caching/CacheStore.java
index 95278c7465ab05169ec12cb0cf7a04a98c836a82..1f47483078520feb66bf366b348a512e0d661f06 100644
--- a/caching/src/main/java/com/iluwatar/caching/CacheStore.java
+++ b/caching/src/main/java/com/iluwatar/caching/CacheStore.java
@@ -11,6 +11,9 @@ public class CacheStore {
 
   static LruCache cache = null;
 
+  private CacheStore() {
+  }
+
   /**
    * Init cache capacity
    */
diff --git a/caching/src/main/java/com/iluwatar/caching/DbManager.java b/caching/src/main/java/com/iluwatar/caching/DbManager.java
index 499ad5c3caa0feccb74a6ddedb11e4c8f4b345cb..bfde07103ae64382f755f300170cc386e50826e2 100644
--- a/caching/src/main/java/com/iluwatar/caching/DbManager.java
+++ b/caching/src/main/java/com/iluwatar/caching/DbManager.java
@@ -29,6 +29,9 @@ public class DbManager {
 
   private static HashMap<String, UserAccount> virtualDB;
 
+  private DbManager() {
+  }
+
   /**
    * Create DB
    */
diff --git a/naked-objects/integtests/src/test/java/domainapp/integtests/bootstrap/SimpleAppSystemInitializer.java b/naked-objects/integtests/src/test/java/domainapp/integtests/bootstrap/SimpleAppSystemInitializer.java
index 0384b0eb4aeae9ab68bb2bd0a07ec6eb809c8e6f..90ae45d95a017be93e0133c53890abd6d7f48348 100644
--- a/naked-objects/integtests/src/test/java/domainapp/integtests/bootstrap/SimpleAppSystemInitializer.java
+++ b/naked-objects/integtests/src/test/java/domainapp/integtests/bootstrap/SimpleAppSystemInitializer.java
@@ -21,6 +21,9 @@ import org.apache.isis.objectstore.jdo.datanucleus.IsisConfigurationForJdoIntegT
 
 public class SimpleAppSystemInitializer {
 
+  private SimpleAppSystemInitializer() {
+  }
+
   /**
    * Init test system
    */
diff --git a/service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java b/service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java
index fce6fb8736221bddafed2052f0b326d93bc7d31d..efc87dd154c3a86b03db654b69747ba1b581b45e 100644
--- a/service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java
+++ b/service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java
@@ -32,6 +32,9 @@ public class HibernateUtil {
     }
   }
 
+  private HibernateUtil() {
+  }
+
   public static SessionFactory getSessionFactory() {
     return SESSION_FACTORY;
   }
diff --git a/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceLocator.java b/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceLocator.java
index 6df74f84e873e3f54333903b4ed6366494025ad5..6fb361ca6af9fda92e95df36a81c36ad11b0b573 100644
--- a/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceLocator.java
+++ b/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceLocator.java
@@ -10,6 +10,9 @@ public class ServiceLocator {
 
   private static ServiceCache serviceCache = new ServiceCache();
 
+  private ServiceLocator() {
+  }
+
   /**
    * Fetch the service with the name param from the cache first, if no service is found, lookup the
    * service from the {@link InitContext} and then add the newly created service into the cache map
diff --git a/tolerant-reader/src/main/java/com/iluwatar/tolerantreader/RainbowFishSerializer.java b/tolerant-reader/src/main/java/com/iluwatar/tolerantreader/RainbowFishSerializer.java
index 6a9cd34b278e69aa2d92df8a34c23cc3db2a2de8..5d2a13735fba8c55c73344e9c6670f613d784656 100644
--- a/tolerant-reader/src/main/java/com/iluwatar/tolerantreader/RainbowFishSerializer.java
+++ b/tolerant-reader/src/main/java/com/iluwatar/tolerantreader/RainbowFishSerializer.java
@@ -18,6 +18,9 @@ import java.util.Map;
  */
 public class RainbowFishSerializer {
 
+  private RainbowFishSerializer() {
+  }
+
   /**
    * Write V1 RainbowFish to file
    */