diff --git a/filterer/README.MD b/filterer/README.MD
index b8207af6f..0c03e21a9 100644
--- a/filterer/README.MD
+++ b/filterer/README.MD
@@ -14,7 +14,7 @@ tags:
 Filterer
 
 ## Intent
-The intent of this design pattern is to to introduce a functional interface that will add a functionality for container-like objects to easily return filtered versions of themselves.
+The intent of this design pattern is to introduce a functional interface that will add a functionality for container-like objects to easily return filtered versions of themselves.
 
 ## Explanation
 Real world example
@@ -59,7 +59,7 @@ The container-like object (`ThreatAwareSystem` in our case) needs to have a meth
 ability to covariantly specify a lower bound of contravariant `Predicate` in the subinterfaces of interfaces representing the container-like objects.
 
 In our example we will be able to pass a predicate that takes `? extends Threat` object and return `?  extends ThreatAwareSystem`
-from `Filtered::by` method. A simple implementation of `ThreadAwareSystem` :
+from `Filtered::by` method. A simple implementation of `ThreatAwareSystem` :
 ```java
 public class SimpleThreatAwareSystem implements ThreatAwareSystem {
 
@@ -99,7 +99,7 @@ public class SimpleThreatAwareSystem implements ThreatAwareSystem {
 ```
 the `filtered` method is overridden to filter the threats list by given predicate.
 
-Now if we introduce new subtype of `Thread` interface that adds probability with which given thread can appear :
+Now if we introduce a new subtype of `Threat` interface that adds probability with which given threat can appear :
 ```java
 public interface ProbableThreat extends Threat {
   double probability();
@@ -116,7 +116,7 @@ public interface ProbabilisticThreatAwareSystem extends ThreatAwareSystem {
 }
 ````
 Notice how we override the `filtered` method in `ProbabilisticThreatAwareSystem` and specify different return covariant type
-by specifing different generic types. Our interfaces are clean and not cluttered by default implementations. We
+by specifying different generic types. Our interfaces are clean and not cluttered by default implementations. We
 we will be able to filter `ProbabilisticThreatAwareSystem` by `ProbableThreat` properties :
 ```java
 public class SimpleProbabilisticThreatAwareSystem implements ProbabilisticThreatAwareSystem {
diff --git a/filterer/src/main/java/com/iluwatar/filterer/App.java b/filterer/src/main/java/com/iluwatar/filterer/App.java
index 97ed24837..43de5a646 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/App.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/App.java
@@ -23,7 +23,6 @@
 
 package com.iluwatar.filterer;
 
-import com.iluwatar.filterer.threat.ProbabilisticThreatAwareSystem;
 import com.iluwatar.filterer.threat.ProbableThreat;
 import com.iluwatar.filterer.threat.SimpleProbabilisticThreatAwareSystem;
 import com.iluwatar.filterer.threat.SimpleProbableThreat;
@@ -65,24 +64,22 @@ public class App {
   private static void filteringSimpleProbableThreats() {
     LOGGER.info(" ### Filtering ProbabilisticThreatAwareSystem by probability ###");
 
-    ProbableThreat trojanArcBomb =
-            new SimpleProbableThreat("Trojan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
-    ProbableThreat rootkit =
-            new SimpleProbableThreat("Rootkit-Kernel", 2, ThreatType.ROOTKIT, 0.8);
+    var trojanArcBomb = new SimpleProbableThreat("Trojan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
+    var rootkit = new SimpleProbableThreat("Rootkit-Kernel", 2, ThreatType.ROOTKIT, 0.8);
 
     List<ProbableThreat> probableThreats = List.of(trojanArcBomb, rootkit);
 
-    ProbabilisticThreatAwareSystem probabilisticThreatAwareSystem =
-            new SimpleProbabilisticThreatAwareSystem("System-1", probableThreats);
+    var probabilisticThreatAwareSystem =
+            new SimpleProbabilisticThreatAwareSystem("Sys-1", probableThreats);
 
     LOGGER.info("Filtering ProbabilisticThreatAwareSystem. Initial : "
             + probabilisticThreatAwareSystem);
 
     //Filtering using filterer
-    ProbabilisticThreatAwareSystem filtered = probabilisticThreatAwareSystem.filtered()
+    var filteredThreatAwareSystem = probabilisticThreatAwareSystem.filtered()
             .by(probableThreat -> Double.compare(probableThreat.probability(), 0.99) == 0);
 
-    LOGGER.info("Filtered by probability = 0.99 : " + filtered);
+    LOGGER.info("Filtered by probability = 0.99 : " + filteredThreatAwareSystem);
   }
 
   /**
@@ -93,16 +90,16 @@ public class App {
   private static void filteringSimpleThreats() {
     LOGGER.info("### Filtering ThreatAwareSystem by ThreatType ###");
 
-    Threat rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
-    Threat trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
+    var rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
+    var trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
     List<Threat> threats = List.of(rootkit, trojan);
 
-    ThreatAwareSystem threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
+    var threatAwareSystem = new SimpleThreatAwareSystem("Sys-1", threats);
 
     LOGGER.info("Filtering ThreatAwareSystem. Initial : " + threatAwareSystem);
 
     //Filtering using Filterer
-    ThreatAwareSystem rootkitThreatAwareSystem = threatAwareSystem.filtered()
+    var rootkitThreatAwareSystem = threatAwareSystem.filtered()
             .by(threat -> threat.type() == ThreatType.ROOTKIT);
 
     LOGGER.info("Filtered by threatType = ROOTKIT : " + rootkitThreatAwareSystem);
diff --git a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
index 37fae6a74..3991d975e 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
@@ -93,7 +93,7 @@ public class SimpleProbabilisticThreatAwareSystem implements ProbabilisticThreat
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleProbabilisticThreatAwareSystem that = (SimpleProbabilisticThreatAwareSystem) o;
+    var that = (SimpleProbabilisticThreatAwareSystem) o;
     return systemId.equals(that.systemId)
             && threats.equals(that.threats);
   }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
index 27efc740a..54da07873 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
@@ -60,7 +60,7 @@ public class SimpleProbableThreat extends SimpleThreat implements ProbableThreat
     if (!super.equals(o)) {
       return false;
     }
-    SimpleProbableThreat that = (SimpleProbableThreat) o;
+    var that = (SimpleProbableThreat) o;
     return Double.compare(that.probability, probability) == 0;
   }
 
diff --git a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
index fe7f155d4..08a8b0e17 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
@@ -79,7 +79,7 @@ public class SimpleThreat implements Threat {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleThreat that = (SimpleThreat) o;
+    var that = (SimpleThreat) o;
     return id == that.id
             && threatType == that.threatType
             && Objects.equals(name, that.name);
diff --git a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
index 49707cf50..f1dec40ae 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
@@ -87,7 +87,7 @@ public class SimpleThreatAwareSystem implements ThreatAwareSystem {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleThreatAwareSystem that = (SimpleThreatAwareSystem) o;
+    var that = (SimpleThreatAwareSystem) o;
     return systemId.equals(that.systemId)
             && issues.equals(that.issues);
   }
diff --git a/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
index 592fabe88..2f14ca057 100644
--- a/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
+++ b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
@@ -33,15 +33,15 @@ class SimpleProbabilisticThreatAwareSystemTest {
   @Test
   void shouldFilterByProbability() {
     //given
-    ProbableThreat trojan = new SimpleProbableThreat("Troyan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
-    ProbableThreat rootkit = new SimpleProbableThreat("Rootkit-System", 2, ThreatType.ROOTKIT, 0.8);
+    var trojan = new SimpleProbableThreat("Troyan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
+    var rootkit = new SimpleProbableThreat("Rootkit-System", 2, ThreatType.ROOTKIT, 0.8);
     List<ProbableThreat> probableThreats = List.of(trojan, rootkit);
 
-    ProbabilisticThreatAwareSystem simpleProbabilisticThreatAwareSystem =
+    var simpleProbabilisticThreatAwareSystem =
             new SimpleProbabilisticThreatAwareSystem("System-1", probableThreats);
 
     //when
-    ProbabilisticThreatAwareSystem filtered = simpleProbabilisticThreatAwareSystem.filtered()
+    var filtered = simpleProbabilisticThreatAwareSystem.filtered()
             .by(probableThreat -> Double.compare(probableThreat.probability(), 0.99) == 0);
 
     //then
diff --git a/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
index 91fb62718..ea918c9ec 100644
--- a/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
+++ b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
@@ -33,14 +33,14 @@ class SimpleThreatAwareSystemTest {
   @Test
   void shouldFilterByThreatType() {
     //given
-    Threat rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
-    Threat trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
+    var rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
+    var trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
     List<Threat> threats = List.of(rootkit, trojan);
 
-    ThreatAwareSystem threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
+    var threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
 
     //when
-    ThreatAwareSystem rootkitThreatAwareSystem = threatAwareSystem.filtered()
+    var rootkitThreatAwareSystem = threatAwareSystem.filtered()
             .by(threat -> threat.type() == ThreatType.ROOTKIT);
 
     //then