diff --git a/filterer/README.MD b/filterer/README.MD
index 8a2526048..3281e9ecc 100644
--- a/filterer/README.MD
+++ b/filterer/README.MD
@@ -1,6 +1,6 @@
 --- # this is so called 'Yaml Front Matter', read up on it here: http://jekyllrb.com/docs/frontmatter/
 layout: pattern
-title: Filterer Pattern
+title: Filterer
 folder: filterer
 permalink: /patterns/filterer/
 description: Design pattern that helps container-like objects to return filtered version of themselves.# short meta description that shows in Google search results
@@ -11,15 +11,173 @@ tags:
 ---
 
 ## Name / classification
-Filterer Pattern
+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.
 
 ## Explanation
-The container-like object needs to have a method that returns an instance of `Filterer`. This helper interface gives 
+Real world example
+
+> We are designing a threat(malware) detection system. We can have different types of threats and systems. We have a requirement that
+> system should be aware of threats that are present in it. In the design we have to take into consideration that new Threat types can be
+> added later. Also there is a requirement that a system can filter itself based on the threats that it possesses (system acts as container-like object for threats).
+>
+
+In plain words
+
+> We need to be able to filter different types of systems(container-like objects) based on properties of Threats that they contain.
+> Adding new properties for Threats should be easy (we still need the ability to filter by those new properties).
+
+**Programmatic Example**
+
+To model the threat detection example presented above we introduce `Threat` and `ThreatAwareSystem` interfaces.
+
+```java
+public interface Threat {
+  String name();
+  int id();
+  ThreatType type();
+}
+
+public interface ThreatAwareSystem {
+  String systemId();
+  List<? extends Threat> threats();
+  Filterer<? extends ThreatAwareSystem, ? extends Threat> filtered();
+
+}
+```
+Notice the `filtered` method that returns instance of `Filterer` interface which is defined as :
+```java
+@FunctionalInterface
+public interface Filterer<G, E> {
+  G by(Predicate<? super E> predicate);
+}
+```
+it is used to fulfill the requirement for system to be able to filter itself based on threat properties.
+The container-like object (`ThreatAwareSystem` in our case) needs to have a method that returns an instance of `Filterer`. This helper interface gives 
 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` :
+```java
+public class SimpleThreatAwareSystem implements ThreatAwareSystem {
+
+  private final String systemId;
+  private final ImmutableList<Threat> issues;
+
+  public SimpleThreatAwareSystem(final String systemId, final List<Threat> issues) {
+    this.systemId = systemId;
+    this.issues = ImmutableList.copyOf(issues);
+  }
+  
+  @Override
+  public String systemId() {
+    return systemId;
+  }
+  
+  @Override
+  public List<? extends Threat> threats() {
+    return new ArrayList<>(issues);
+  }
+
+  @Override
+  public Filterer<? extends ThreatAwareSystem, ? extends Threat> filtered() {
+    return this::filteredGroup;
+  }
+
+  private ThreatAwareSystem filteredGroup(Predicate<? super Threat> predicate) {
+    return new SimpleThreatAwareSystem(this.systemId, filteredItems(predicate));
+  }
+
+  private List<Threat> filteredItems(Predicate<? super Threat> predicate) {
+    return this.issues.stream()
+            .filter(predicate)
+            .collect(Collectors.toList());
+  }
+}
+```
+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 :
+```java
+public interface ProbableThreat extends Threat {
+  double probability();
+}
+```
+we can also introduce a new interface that represents a system that is aware of threats with their probabilities :
+````java
+public interface ProbabilisticThreatAwareSystem extends ThreatAwareSystem {
+  @Override
+  List<? extends ProbableThreat> threats();
+
+  @Override
+  Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat> filtered();
+}
+````
+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
+we will be able to filter `ProbabilisticThreatAwareSystem` by `ProbableThreat` properties :
+```java
+public class SimpleProbabilisticThreatAwareSystem implements ProbabilisticThreatAwareSystem {
+
+  private final String systemId;
+  private final ImmutableList<ProbableThreat> threats;
+
+  public SimpleProbabilisticThreatAwareSystem(final String systemId, final List<ProbableThreat> threats) {
+    this.systemId = systemId;
+    this.threats = ImmutableList.copyOf(threats);
+  }
+
+  @Override
+  public String systemId() {
+    return systemId;
+  }
+
+  @Override
+  public List<? extends ProbableThreat> threats() {
+    return threats;
+  }
+
+  @Override
+  public Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat> filtered() {
+    return this::filteredGroup;
+  }
+
+  private ProbabilisticThreatAwareSystem filteredGroup(final Predicate<? super ProbableThreat> predicate) {
+    return new SimpleProbabilisticThreatAwareSystem(this.systemId, filteredItems(predicate));
+  }
+
+  private List<ProbableThreat> filteredItems(final Predicate<? super ProbableThreat> predicate) {
+    return this.threats.stream()
+            .filter(predicate)
+            .collect(Collectors.toList());
+  }
+}
+```
+
+Now if we want filter `ThreatAwareSystem` by threat type we can do :
+```java
+Threat rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
+Threat trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
+List<Threat> threats = List.of(rootkit, trojan);
+
+ThreatAwareSystem threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
+
+ThreatAwareSystem rootkitThreatAwareSystem = threatAwareSystem.filtered()
+           .by(threat -> threat.type() == ThreatType.ROOTKIT);
+```
+or if we want to filter `ProbabilisticThreatAwareSystem` :
+```java
+ProbableThreat malwareTroyan = new SimpleProbableThreat("Troyan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
+ProbableThreat rootkit = new SimpleProbableThreat("Rootkit-System", 2, ThreatType.ROOTKIT, 0.8);
+List<ProbableThreat> probableThreats = List.of(malwareTroyan, rootkit);
+
+ProbabilisticThreatAwareSystem simpleProbabilisticThreatAwareSystem =new SimpleProbabilisticThreatAwareSystem("System-1", probableThreats);
+
+ProbabilisticThreatAwareSystem filtered = simpleProbabilisticThreatAwareSystem.filtered()
+           .by(probableThreat -> Double.compare(probableThreat.probability(), 0.99) == 0);
+```
 ## Class diagram
 ![Filterer](./etc/filterer.png "Filterer")
 
@@ -34,11 +192,11 @@ It enables you to easily extend filtering ability of container-like objects as b
 ## Known uses
 One of the uses is present on the blog presented in this link. It presents how to use `Filterer` pattern to create text issue anaylyzer with support for test cases used for unit testing.
 
-## Consequences (the good and the bad, add criticism here)
-Good :
+## Consequences
+Pros :
  * you can easily introduce new subtypes for container-like objects and subtypes for objects that are contained within them and still be able to filter easily be new properties of those new subtypes.
 
-Bad :
+Cons :
  * covariant return types mixed with generics can be sometimes tricky
 
 ## Credits
diff --git a/filterer/etc/filterer.png b/filterer/etc/filterer.png
index f86764aa3..6a6eb059b 100644
Binary files a/filterer/etc/filterer.png and b/filterer/etc/filterer.png differ
diff --git a/filterer/etc/filterer.urm.puml b/filterer/etc/filterer.urm.puml
index 24060b6aa..c0bb0b54d 100644
--- a/filterer/etc/filterer.urm.puml
+++ b/filterer/etc/filterer.urm.puml
@@ -4,129 +4,93 @@ package com.iluwatar.filterer.domain {
     + by(Predicate<? super E>) : G {abstract}
   }
 }
-package com.iluwatar.filterer.issue {
-  interface Issue {
-    + endOffset() : int {abstract}
-    + startOffset() : int {abstract}
-    + type() : IssueType {abstract}
+package com.iluwatar.filterer {
+  class App {
+    - LOGGER : Logger {static}
+    + App()
+    - filteringSimpleProbableThreats() {static}
+    - filteringSimpleThreats() {static}
+    + main(args : String[]) {static}
   }
-  interface IssueAwareText {
-    + filtered() : Filterer<? extends IssueAwareText, ? extends Issue> {abstract}
-    + issues() : List<? extends Issue> {abstract}
-    + text() : String {abstract}
+}
+package com.iluwatar.filterer.threat {
+  interface ProbabilisticThreatAwareSystem {
+    + filtered() : Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat> {abstract}
+    + threats() : List<? extends ProbableThreat> {abstract}
   }
-  class IssuePosition {
-    - endOffset : int
-    - startOffset : int
-    - IssuePosition(startOffset : int, endOffset : int)
-    ~ endOffset() : int
-    + equals(o : Object) : boolean
-    + hashCode() : int
-    + of(startOffset : int, endOffset : int) : IssuePosition {static}
-    ~ startOffset() : int
-  }
-  ~enum IssueType {
-    + GRAMMAR {static}
-    + SPELLING {static}
-    + valueOf(name : String) : IssueType {static}
-    + values() : IssueType[] {static}
-  }
-  interface IssueWiseText {
-    + filtered() : Filterer<? extends IssueWiseText, ? extends Issue> {abstract}
-    + issues() : List<? extends Issue> {abstract}
-    + text() : String {abstract}
-  }
-  interface ProbabilisticIssueAwareText {
-    + filtered() : Filterer<? extends ProbabilisticIssueAwareText, ? extends ProbableIssue> {abstract}
-    + issues() : List<? extends ProbableIssue> {abstract}
-  }
-  interface ProbabilisticIssueWiseText {
-    + filtered() : Filterer<? extends ProbabilisticIssueWiseText, ? extends ProbableIssue> {abstract}
-    + issues() : List<? extends ProbableIssue> {abstract}
-  }
-  interface ProbableIssue {
+  interface ProbableThreat {
     + probability() : double {abstract}
   }
-  class SimpleIssue {
-    - issuePosition : IssuePosition
-    - issueType : IssueType
-    ~ SimpleIssue(issuePosition : IssuePosition, issueType : IssueType)
-    + endOffset() : int
+  class SimpleProbabilisticThreatAwareSystem {
+    - systemId : String
+    - threats : ImmutableList<ProbableThreat>
+    + SimpleProbabilisticThreatAwareSystem(systemId : String, threats : List<ProbableThreat>)
     + equals(o : Object) : boolean
+    + filtered() : Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat>
+    - filteredGroup(predicate : Predicate<? super ProbableThreat>) : ProbabilisticThreatAwareSystem
+    - filteredItems(predicate : Predicate<? super ProbableThreat>) : List<ProbableThreat>
     + hashCode() : int
-    + startOffset() : int
-    + type() : IssueType
+    + systemId() : String
+    + threats() : List<? extends ProbableThreat>
+    + toString() : String
   }
-  class SimpleIssueAwareText {
-    - issues : ImmutableList<Issue>
-    - text : String
-    ~ SimpleIssueAwareText(text : String, issues : List<Issue>)
-    + equals(o : Object) : boolean
-    + filtered() : Filterer<? extends IssueAwareText, ? extends Issue>
-    - filteredGroup(predicate : Predicate<? super Issue>) : IssueAwareText
-    - filteredItems(predicate : Predicate<? super Issue>) : ImmutableList<Issue>
-    + hashCode() : int
-    + issues() : List<? extends Issue>
-    + text() : String
-  }
-  class SimpleIssueWiseText {
-    - issues : ImmutableList<Issue>
-    - text : String
-    + SimpleIssueWiseText(text : String, issues : List<Issue>)
-    + equals(o : Object) : boolean
-    + filtered() : Filterer<? extends IssueWiseText, ? extends Issue>
-    - filteredGroup(predicate : Predicate<? super Issue>) : IssueWiseText
-    - filteredItems(predicate : Predicate<? super Issue>) : ImmutableList<Issue>
-    + hashCode() : int
-    + issues() : List<? extends Issue>
-    + text() : String
-  }
-  class SimpleProbabilisticIssueAwareText {
-    - issues : ImmutableList<ProbableIssue>
-    - text : String
-    ~ SimpleProbabilisticIssueAwareText(text : String, issues : List<ProbableIssue>)
-    + equals(o : Object) : boolean
-    + filtered() : Filterer<? extends ProbabilisticIssueAwareText, ? extends ProbableIssue>
-    - filteredGroup(predicate : Predicate<? super ProbableIssue>) : ProbabilisticIssueAwareText
-    - filteredItems(predicate : Predicate<? super ProbableIssue>) : ImmutableList<ProbableIssue>
-    + hashCode() : int
-    + issues() : List<? extends ProbableIssue>
-    + text() : String
-  }
-  class SimpleProbabilisticIssueWiseText {
-    - issues : ImmutableList<ProbableIssue>
-    - text : String
-    + SimpleProbabilisticIssueWiseText(text : String, issues : List<ProbableIssue>)
-    + equals(o : Object) : boolean
-    + filtered() : Filterer<? extends ProbabilisticIssueWiseText, ? extends ProbableIssue>
-    - filteredGroup(predicate : Predicate<? super ProbableIssue>) : ProbabilisticIssueWiseText
-    - filteredItems(predicate : Predicate<? super ProbableIssue>) : ImmutableList<ProbableIssue>
-    + hashCode() : int
-    + issues() : List<? extends ProbableIssue>
-    + text() : String
-  }
-  class SimpleProbableIssue {
+  class SimpleProbableThreat {
     - probability : double
-    ~ SimpleProbableIssue(issuePosition : IssuePosition, issueType : IssueType, probability : double)
+    + SimpleProbableThreat(name : String, id : int, threatType : ThreatType, probability : double)
     + equals(o : Object) : boolean
     + hashCode() : int
     + probability() : double
+    + toString() : String
+  }
+  class SimpleThreat {
+    - id : int
+    - name : String
+    - threatType : ThreatType
+    + SimpleThreat(threatType : ThreatType, id : int, name : String)
+    + id() : int
+    + name() : String
+    + toString() : String
+    + type() : ThreatType
+  }
+  class SimpleThreatAwareSystem {
+    - issues : ImmutableList<Threat>
+    - systemId : String
+    + SimpleThreatAwareSystem(systemId : String, issues : List<Threat>)
+    + equals(o : Object) : boolean
+    + filtered() : Filterer<? extends ThreatAwareSystem, ? extends Threat>
+    - filteredGroup(predicate : Predicate<? super Threat>) : ThreatAwareSystem
+    - filteredItems(predicate : Predicate<? super Threat>) : List<Threat>
+    + hashCode() : int
+    + systemId() : String
+    + threats() : List<? extends Threat>
+    + toString() : String
+  }
+  interface Threat {
+    + id() : int {abstract}
+    + name() : String {abstract}
+    + type() : ThreatType {abstract}
+  }
+  interface ThreatAwareSystem {
+    + filtered() : Filterer<? extends ThreatAwareSystem, ? extends Threat> {abstract}
+    + systemId() : String {abstract}
+    + threats() : List<? extends Threat> {abstract}
+  }
+  enum ThreatType {
+    + ROOTKIT {static}
+    + TROJAN {static}
+    + WORM {static}
+    + valueOf(name : String) : ThreatType {static}
+    + values() : ThreatType[] {static}
   }
 }
-SimpleIssueWiseText -->  "-issues" Issue
-SimpleProbabilisticIssueAwareText -->  "-issues" ProbableIssue
-SimpleIssue -->  "-issueType" IssueType
-SimpleIssueAwareText -->  "-issues" Issue
-SimpleProbabilisticIssueWiseText -->  "-issues" ProbableIssue
-SimpleIssue -->  "-issuePosition" IssuePosition
-ProbabilisticIssueAwareText --|> IssueAwareText 
-ProbabilisticIssueWiseText --|> IssueWiseText 
-ProbableIssue --|> Issue 
-SimpleIssue ..|> Issue 
-SimpleIssueAwareText ..|> IssueAwareText 
-SimpleIssueWiseText ..|> IssueWiseText 
-SimpleProbabilisticIssueAwareText ..|> ProbabilisticIssueAwareText 
-SimpleProbabilisticIssueWiseText ..|> ProbabilisticIssueWiseText 
-SimpleProbableIssue ..|> ProbableIssue 
-SimpleProbableIssue --|> SimpleIssue 
+SimpleThreatAwareSystem -->  "-issues" Threat
+SimpleThreat -->  "-threatType" ThreatType
+SimpleProbabilisticThreatAwareSystem -->  "-threats" ProbableThreat
+ProbabilisticThreatAwareSystem --|> ThreatAwareSystem 
+ProbableThreat --|> Threat 
+SimpleProbabilisticThreatAwareSystem ..|> ProbabilisticThreatAwareSystem 
+SimpleProbableThreat ..|> ProbableThreat 
+SimpleProbableThreat --|> SimpleThreat 
+SimpleThreat ..|> Threat 
+SimpleThreatAwareSystem ..|> ThreatAwareSystem 
 @enduml
\ No newline at end of file
diff --git a/filterer/pom.xml b/filterer/pom.xml
index 24dae571e..4477332ae 100644
--- a/filterer/pom.xml
+++ b/filterer/pom.xml
@@ -39,37 +39,34 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>29.0-jre</version>
         </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.6.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>
-            <version>5.6.2</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>3.16.1</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
-
     <build>
         <plugins>
             <plugin>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.22.2</version>
-            </plugin>
-            <plugin>
-                <artifactId>maven-failsafe-plugin</artifactId>
-                <version>2.22.2</version>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <configuration>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.iluwatar.filterer.App</mainClass>
+                                </manifest>
+                            </archive>
+                        </configuration>
+                    </execution>
+                </executions>
             </plugin>
         </plugins>
     </build>
diff --git a/filterer/src/main/java/com/iluwatar/filterer/App.java b/filterer/src/main/java/com/iluwatar/filterer/App.java
new file mode 100644
index 000000000..97ed24837
--- /dev/null
+++ b/filterer/src/main/java/com/iluwatar/filterer/App.java
@@ -0,0 +1,111 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+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;
+import com.iluwatar.filterer.threat.SimpleThreat;
+import com.iluwatar.filterer.threat.SimpleThreatAwareSystem;
+import com.iluwatar.filterer.threat.Threat;
+import com.iluwatar.filterer.threat.ThreatAwareSystem;
+import com.iluwatar.filterer.threat.ThreatType;
+
+import java.util.List;
+import java.util.function.Predicate;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This demo class represent how {@link com.iluwatar.filterer.domain.Filterer} pattern is used to
+ * filter container-like objects to return filtered versions of themselves. The container like
+ * objects are systems that are aware of threats that they can be vulnerable to. We would like
+ * to have a way to create copy of different system objects but with filtered threats.
+ * The thing is to keep it simple if we add new subtype of {@link Threat}
+ * (for example {@link ProbableThreat}) - we still need to be able to filter by it's properties.
+ */
+public class App {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  public static void main(String[] args) {
+    filteringSimpleThreats();
+    filteringSimpleProbableThreats();
+  }
+
+  /**
+   * Demonstrates how to filter {@link com.iluwatar.filterer.threat.ProbabilisticThreatAwareSystem}
+   * based on probability property. The @{@link com.iluwatar.filterer.domain.Filterer#by(Predicate)}
+   * method is able to use {@link com.iluwatar.filterer.threat.ProbableThreat}
+   * as predicate argument.
+   */
+  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);
+
+    List<ProbableThreat> probableThreats = List.of(trojanArcBomb, rootkit);
+
+    ProbabilisticThreatAwareSystem probabilisticThreatAwareSystem =
+            new SimpleProbabilisticThreatAwareSystem("System-1", probableThreats);
+
+    LOGGER.info("Filtering ProbabilisticThreatAwareSystem. Initial : "
+            + probabilisticThreatAwareSystem);
+
+    //Filtering using filterer
+    ProbabilisticThreatAwareSystem filtered = probabilisticThreatAwareSystem.filtered()
+            .by(probableThreat -> Double.compare(probableThreat.probability(), 0.99) == 0);
+
+    LOGGER.info("Filtered by probability = 0.99 : " + filtered);
+  }
+
+  /**
+   * Demonstrates how to filter {@link ThreatAwareSystem} based on startingOffset property
+   * of {@link SimpleThreat}. The @{@link com.iluwatar.filterer.domain.Filterer#by(Predicate)}
+   * method is able to use {@link Threat} as predicate argument.
+   */
+  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");
+    List<Threat> threats = List.of(rootkit, trojan);
+
+    ThreatAwareSystem threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
+
+    LOGGER.info("Filtering ThreatAwareSystem. Initial : " + threatAwareSystem);
+
+    //Filtering using Filterer
+    ThreatAwareSystem 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/issue/IssuePosition.java b/filterer/src/main/java/com/iluwatar/filterer/issue/IssuePosition.java
deleted file mode 100644
index a771c1a82..000000000
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/IssuePosition.java
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-package com.iluwatar.filterer.issue;
-
-import java.util.Objects;
-
-/**
- * Represents position of an issue. Takes starting and ending offset of issue in given text.
- */
-public final class IssuePosition {
-
-  private final int startOffset;
-  private final int endOffset;
-
-  /**
-   * Factory method for constructing `IssuePosition` instances.
-   * @param startOffset starting offset of where the issue begins.
-   * @param endOffset ending offset of where the issue ends.
-   * @return new IssuePosition instance.
-   */
-  public static IssuePosition of(final int startOffset, final int endOffset) {
-    return new IssuePosition(startOffset, endOffset);
-  }
-
-  private IssuePosition(int startOffset, int endOffset) {
-    this.startOffset = startOffset;
-    this.endOffset = endOffset;
-  }
-
-  int startOffset() {
-    return startOffset;
-  }
-
-  int endOffset() {
-    return endOffset;
-  }
-
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    IssuePosition that = (IssuePosition) o;
-    return startOffset == that.startOffset
-            && endOffset == that.endOffset;
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(startOffset, endOffset);
-  }
-}
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/ProbabilisticIssueAwareText.java b/filterer/src/main/java/com/iluwatar/filterer/threat/ProbabilisticThreatAwareSystem.java
similarity index 79%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/ProbabilisticIssueAwareText.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/ProbabilisticThreatAwareSystem.java
index da15bdd99..3a2959828 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/ProbabilisticIssueAwareText.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/ProbabilisticThreatAwareSystem.java
@@ -21,29 +21,29 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import com.iluwatar.filterer.domain.Filterer;
 
 import java.util.List;
 
 /**
- * Represents text that is aware of it's issues with given probability of their occurrence.
+ * Represents system that is aware of it's threats with given probability of their occurrence.
  */
-public interface ProbabilisticIssueAwareText extends IssueAwareText {
+public interface ProbabilisticThreatAwareSystem extends ThreatAwareSystem {
 
   /**
    * {@inheritDoc}
    * @return
    */
   @Override
-  List<? extends ProbableIssue> issues();
+  List<? extends ProbableThreat> threats();
 
   /**
    * {@inheritDoc}
    * @return
    */
   @Override
-  Filterer<? extends ProbabilisticIssueAwareText, ? extends ProbableIssue> filtered();
+  Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat> filtered();
 }
 
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/ProbableIssue.java b/filterer/src/main/java/com/iluwatar/filterer/threat/ProbableThreat.java
similarity index 81%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/ProbableIssue.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/ProbableThreat.java
index ccb047fa4..11e61dbf6 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/ProbableIssue.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/ProbableThreat.java
@@ -21,15 +21,15 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 /**
- * Represents issue that is an issue with given probability.
+ * Represents threat that might be a threat with given probability.
  */
-public interface ProbableIssue extends Issue {
+public interface ProbableThreat extends Threat {
   /**
-   * Returns probability of occurrence of given issue.
-   * @return probability of occurrence of given issue.
+   * Returns probability of occurrence of given threat.
+   * @return probability of occurrence of given threat.
    */
   double probability();
 }
\ No newline at end of file
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareText.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
similarity index 54%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareText.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
index e1b4afc82..37fae6a74 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareText.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystem.java
@@ -21,7 +21,7 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import com.google.common.collect.ImmutableList;
 import com.iluwatar.filterer.domain.Filterer;
@@ -29,56 +29,60 @@ import com.iluwatar.filterer.domain.Filterer;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 /**
  * {@inheritDoc}
  */
-public class SimpleProbabilisticIssueAwareText implements ProbabilisticIssueAwareText {
+public class SimpleProbabilisticThreatAwareSystem implements ProbabilisticThreatAwareSystem {
 
-  private final String text;
-  private final ImmutableList<ProbableIssue> issues;
+  private final String systemId;
+  private final ImmutableList<ProbableThreat> threats;
 
-  SimpleProbabilisticIssueAwareText(final String text, final List<ProbableIssue> issues) {
-    this.text = text;
-    this.issues = ImmutableList.copyOf(issues);
+  public SimpleProbabilisticThreatAwareSystem(
+          final String systemId,
+          final List<ProbableThreat> threats
+  ) {
+    this.systemId = systemId;
+    this.threats = ImmutableList.copyOf(threats);
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public String text() {
-    return text;
+  public String systemId() {
+    return systemId;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public List<? extends ProbableIssue> issues() {
-    return issues;
+  public List<? extends ProbableThreat> threats() {
+    return threats;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public Filterer<? extends ProbabilisticIssueAwareText, ? extends ProbableIssue> filtered() {
+  public Filterer<? extends ProbabilisticThreatAwareSystem, ? extends ProbableThreat> filtered() {
     return this::filteredGroup;
   }
 
-  private ProbabilisticIssueAwareText filteredGroup(
-          final Predicate<? super ProbableIssue> predicate
+  private ProbabilisticThreatAwareSystem filteredGroup(
+          final Predicate<? super ProbableThreat> predicate
   ) {
-    return new SimpleProbabilisticIssueAwareText(this.text, filteredItems(predicate));
+    return new SimpleProbabilisticThreatAwareSystem(this.systemId, filteredItems(predicate));
   }
 
-  private ImmutableList<ProbableIssue> filteredItems(
-          final Predicate<? super ProbableIssue> predicate
+  private List<ProbableThreat> filteredItems(
+          final Predicate<? super ProbableThreat> predicate
   ) {
-    return this.issues.stream()
+    return this.threats.stream()
             .filter(predicate)
-            .collect(ImmutableList.toImmutableList());
+            .collect(Collectors.toList());
   }
 
   @Override
@@ -89,13 +93,21 @@ public class SimpleProbabilisticIssueAwareText implements ProbabilisticIssueAwar
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleProbabilisticIssueAwareText that = (SimpleProbabilisticIssueAwareText) o;
-    return text.equals(that.text)
-            && issues.equals(that.issues);
+    SimpleProbabilisticThreatAwareSystem that = (SimpleProbabilisticThreatAwareSystem) o;
+    return systemId.equals(that.systemId)
+            && threats.equals(that.threats);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(text, issues);
+    return Objects.hash(systemId, threats);
+  }
+
+  @Override
+  public String toString() {
+    return "SimpleProbabilisticThreatAwareSystem{"
+            + "systemId='" + systemId + '\''
+            + ", threats=" + threats
+            + '}';
   }
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbableIssue.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
similarity index 74%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbableIssue.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
index 2b7672256..27efc740a 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleProbableIssue.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleProbableThreat.java
@@ -21,22 +21,23 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import java.util.Objects;
 
 /**
  * {@inheritDoc}
  */
-public class SimpleProbableIssue extends SimpleIssue implements ProbableIssue {
+public class SimpleProbableThreat extends SimpleThreat implements ProbableThreat {
 
   private final double probability;
 
-  SimpleProbableIssue(final IssuePosition issuePosition,
-                      final IssueType issueType,
-                      final double probability
+  public SimpleProbableThreat(final String name,
+                              final int id,
+                              final ThreatType threatType,
+                              final double probability
   ) {
-    super(issuePosition, issueType);
+    super(threatType, id, name);
     this.probability = probability;
   }
 
@@ -59,7 +60,7 @@ public class SimpleProbableIssue extends SimpleIssue implements ProbableIssue {
     if (!super.equals(o)) {
       return false;
     }
-    SimpleProbableIssue that = (SimpleProbableIssue) o;
+    SimpleProbableThreat that = (SimpleProbableThreat) o;
     return Double.compare(that.probability, probability) == 0;
   }
 
@@ -67,4 +68,12 @@ public class SimpleProbableIssue extends SimpleIssue implements ProbableIssue {
   public int hashCode() {
     return Objects.hash(super.hashCode(), probability);
   }
+
+  @Override
+  public String toString() {
+    return "SimpleProbableThreat{"
+            + "probability=" + probability
+            + "} "
+            + super.toString();
+  }
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssue.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
similarity index 59%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssue.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
index fde5b8d8e..fe7f155d4 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssue.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreat.java
@@ -21,42 +21,54 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import java.util.Objects;
 
-public class SimpleIssue implements Issue {
+/**
+ * Represents a simple threat.
+ */
+public class SimpleThreat implements Threat {
 
-  private final IssuePosition issuePosition;
-  private final IssueType issueType;
+  private final ThreatType threatType;
+  private final int id;
+  private final String name;
 
-  SimpleIssue(final IssuePosition issuePosition, IssueType issueType) {
-    this.issuePosition = issuePosition;
-    this.issueType = issueType;
+  /**
+   * Constructor.
+   *
+   * @param threatType {@link ThreatType}.
+   * @param id         threat id.
+   * @param name       threat name.
+   */
+  public SimpleThreat(final ThreatType threatType, final int id, String name) {
+    this.threatType = threatType;
+    this.id = id;
+    this.name = name;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public int startOffset() {
-    return issuePosition.startOffset();
+  public String name() {
+    return name;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public int endOffset() {
-    return issuePosition.endOffset();
+  public int id() {
+    return id;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public IssueType type() {
-    return issueType;
+  public ThreatType type() {
+    return threatType;
   }
 
   @Override
@@ -67,13 +79,23 @@ public class SimpleIssue implements Issue {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleIssue that = (SimpleIssue) o;
-    return issuePosition.equals(that.issuePosition)
-            && issueType == that.issueType;
+    SimpleThreat that = (SimpleThreat) o;
+    return id == that.id
+            && threatType == that.threatType
+            && Objects.equals(name, that.name);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(issuePosition, issueType);
+    return Objects.hash(threatType, id, name);
+  }
+
+  @Override
+  public String toString() {
+    return "SimpleThreat{"
+            + "threatType=" + threatType
+            + ", id=" + id
+            + ", name='" + name + '\''
+            + '}';
   }
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssueAwareText.java b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
similarity index 63%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssueAwareText.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
index c654a3aaa..49707cf50 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/SimpleIssueAwareText.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystem.java
@@ -21,7 +21,7 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import com.google.common.collect.ImmutableList;
 import com.iluwatar.filterer.domain.Filterer;
@@ -30,17 +30,18 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 /**
  * {@inheritDoc}
  */
-public class SimpleIssueAwareText implements IssueAwareText {
+public class SimpleThreatAwareSystem implements ThreatAwareSystem {
 
-  private final String text;
-  private final ImmutableList<Issue> issues;
+  private final String systemId;
+  private final ImmutableList<Threat> issues;
 
-  SimpleIssueAwareText(final String text, final List<Issue> issues) {
-    this.text = text;
+  public SimpleThreatAwareSystem(final String systemId, final List<Threat> issues) {
+    this.systemId = systemId;
     this.issues = ImmutableList.copyOf(issues);
   }
 
@@ -48,15 +49,15 @@ public class SimpleIssueAwareText implements IssueAwareText {
    * {@inheritDoc}
    */
   @Override
-  public String text() {
-    return text;
+  public String systemId() {
+    return systemId;
   }
 
   /**
    * {@inheritDoc}
    */
   @Override
-  public List<? extends Issue> issues() {
+  public List<? extends Threat> threats() {
     return new ArrayList<>(issues);
   }
 
@@ -64,18 +65,18 @@ public class SimpleIssueAwareText implements IssueAwareText {
    * {@inheritDoc}
    */
   @Override
-  public Filterer<? extends IssueAwareText, ? extends Issue> filtered() {
+  public Filterer<? extends ThreatAwareSystem, ? extends Threat> filtered() {
     return this::filteredGroup;
   }
 
-  private IssueAwareText filteredGroup(Predicate<? super Issue> predicate) {
-    return new SimpleIssueAwareText(this.text, filteredItems(predicate));
+  private ThreatAwareSystem filteredGroup(Predicate<? super Threat> predicate) {
+    return new SimpleThreatAwareSystem(this.systemId, filteredItems(predicate));
   }
 
-  private ImmutableList<Issue> filteredItems(Predicate<? super Issue> predicate) {
+  private List<Threat> filteredItems(Predicate<? super Threat> predicate) {
     return this.issues.stream()
             .filter(predicate)
-            .collect(ImmutableList.toImmutableList());
+            .collect(Collectors.toList());
   }
 
   @Override
@@ -86,13 +87,21 @@ public class SimpleIssueAwareText implements IssueAwareText {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    SimpleIssueAwareText that = (SimpleIssueAwareText) o;
-    return text.equals(that.text)
+    SimpleThreatAwareSystem that = (SimpleThreatAwareSystem) o;
+    return systemId.equals(that.systemId)
             && issues.equals(that.issues);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(text, issues);
+    return Objects.hash(systemId, issues);
+  }
+
+  @Override
+  public String toString() {
+    return "SimpleThreatAwareSystem{"
+            + "systemId='" + systemId
+            + '\'' + ", issues=" + issues
+            + '}';
   }
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/Issue.java b/filterer/src/main/java/com/iluwatar/filterer/threat/Threat.java
similarity index 71%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/Issue.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/Threat.java
index 957ade6e5..515b59332 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/Issue.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/Threat.java
@@ -21,29 +21,29 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 /**
- * Represents an issue that can be detected in given text.
+ * Represents a threat that can be detected in given system.
  */
-public interface Issue {
+public interface Threat {
   /**
-   * Returns starting position where the issue begins.
+   * Returns name of the threat.
    *
-   * @return value representing starting position of the issue.
+   * @return value representing name of the threat.
    */
-  int startOffset();
+  String name();
 
   /**
-   * Returns ending position where the issue ends.
+   * Returns unique id of the threat.
    *
-   * @return value representing ending position of the issue.
+   * @return value representing threat id.
    */
-  int endOffset();
+  int id();
 
   /**
-   * Returns issue type.
-   * @return {@link IssueType}
+   * Returns threat type.
+   * @return {@link ThreatType}
    */
-  IssueType type();
+  ThreatType type();
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/IssueAwareText.java b/filterer/src/main/java/com/iluwatar/filterer/threat/ThreatAwareSystem.java
similarity index 78%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/IssueAwareText.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/ThreatAwareSystem.java
index 8141ae849..b889d537d 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/IssueAwareText.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/ThreatAwareSystem.java
@@ -21,35 +21,35 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import com.iluwatar.filterer.domain.Filterer;
 
 import java.util.List;
 
 /**
- * Represents text that is aware of issues that are present in it.
+ * Represents system that is aware of threats that are present in it.
  */
-public interface IssueAwareText {
+public interface ThreatAwareSystem {
 
   /**
-   * Returns the analyzed text.
+   * Returns the system id.
    *
-   * @return the analyzed text.
+   * @return system id.
    */
-  String text();
+  String systemId();
 
   /**
-   * Returns list of issues for this text.
-   * @return list of issues for this text.
+   * Returns list of threats for this system.
+   * @return list of threats for this system.
    */
-  List<? extends Issue> issues();
+  List<? extends Threat> threats();
 
   /**
    * Returns the instance of {@link Filterer} helper interface that allows to covariantly
    * specify lower bound for predicate that we want to filter by.
    * @return an instance of {@link Filterer} helper interface.
    */
-  Filterer<? extends IssueAwareText, ? extends Issue> filtered();
+  Filterer<? extends ThreatAwareSystem, ? extends Threat> filtered();
 
 }
diff --git a/filterer/src/main/java/com/iluwatar/filterer/issue/IssueType.java b/filterer/src/main/java/com/iluwatar/filterer/threat/ThreatType.java
similarity index 92%
rename from filterer/src/main/java/com/iluwatar/filterer/issue/IssueType.java
rename to filterer/src/main/java/com/iluwatar/filterer/threat/ThreatType.java
index ee2c12ce5..5f9a152a8 100644
--- a/filterer/src/main/java/com/iluwatar/filterer/issue/IssueType.java
+++ b/filterer/src/main/java/com/iluwatar/filterer/threat/ThreatType.java
@@ -21,6 +21,6 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
-enum IssueType { GRAMMAR, SPELLING }
+public enum ThreatType { TROJAN, WORM, ROOTKIT }
diff --git a/filterer/src/test/java/com/iluwatar/filterer/AppTest.java b/filterer/src/test/java/com/iluwatar/filterer/AppTest.java
new file mode 100644
index 000000000..551ebcc18
--- /dev/null
+++ b/filterer/src/test/java/com/iluwatar/filterer/AppTest.java
@@ -0,0 +1,33 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.filterer;
+
+import org.junit.jupiter.api.Test;
+
+class AppTest {
+  @Test
+  void shouldLaunchApp() {
+    App.main(new String[]{});
+  }
+}
\ No newline at end of file
diff --git a/filterer/src/test/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareTextTest.java b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
similarity index 60%
rename from filterer/src/test/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareTextTest.java
rename to filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
index 142415111..592fabe88 100644
--- a/filterer/src/test/java/com/iluwatar/filterer/issue/SimpleProbabilisticIssueAwareTextTest.java
+++ b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleProbabilisticThreatAwareSystemTest.java
@@ -21,32 +21,31 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import org.junit.jupiter.api.Test;
 
 import java.util.List;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-class SimpleProbabilisticIssueAwareTextTest {
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
+class SimpleProbabilisticThreatAwareSystemTest {
   @Test
   void shouldFilterByProbability() {
     //given
-    ProbableIssue spellingIssue = new SimpleProbableIssue(IssuePosition.of(4, 5), IssueType.SPELLING, 100);
-    ProbableIssue grammarIssue = new SimpleProbableIssue(IssuePosition.of(8, 12), IssueType.GRAMMAR, 99);
-    List<ProbableIssue> issues = List.of(spellingIssue, grammarIssue);
+    ProbableThreat trojan = new SimpleProbableThreat("Troyan-ArcBomb", 1, ThreatType.TROJAN, 0.99);
+    ProbableThreat rootkit = new SimpleProbableThreat("Rootkit-System", 2, ThreatType.ROOTKIT, 0.8);
+    List<ProbableThreat> probableThreats = List.of(trojan, rootkit);
 
-    SimpleProbabilisticIssueAwareText simpleIssueWiseText = new SimpleProbabilisticIssueAwareText("I mihgt gone there", issues);
+    ProbabilisticThreatAwareSystem simpleProbabilisticThreatAwareSystem =
+            new SimpleProbabilisticThreatAwareSystem("System-1", probableThreats);
 
     //when
-    ProbabilisticIssueAwareText filtered = simpleIssueWiseText.filtered()
-            .by(issue1 -> Double.compare(issue1.probability(), 99) == 0);
+    ProbabilisticThreatAwareSystem filtered = simpleProbabilisticThreatAwareSystem.filtered()
+            .by(probableThreat -> Double.compare(probableThreat.probability(), 0.99) == 0);
 
     //then
-    assertThat(filtered.issues()).hasSize(1);
-    assertThat(filtered.issues()).element(0).isEqualTo(grammarIssue);
+    assertEquals(filtered.threats().size(), 1);
+    assertEquals(filtered.threats().get(0), trojan);
   }
-
 }
\ No newline at end of file
diff --git a/filterer/src/test/java/com/iluwatar/filterer/issue/SimpleIssueAwareTextTest.java b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
similarity index 62%
rename from filterer/src/test/java/com/iluwatar/filterer/issue/SimpleIssueAwareTextTest.java
rename to filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
index 1278128ae..91fb62718 100644
--- a/filterer/src/test/java/com/iluwatar/filterer/issue/SimpleIssueAwareTextTest.java
+++ b/filterer/src/test/java/com/iluwatar/filterer/threat/SimpleThreatAwareSystemTest.java
@@ -21,32 +21,30 @@
  * THE SOFTWARE.
  */
 
-package com.iluwatar.filterer.issue;
+package com.iluwatar.filterer.threat;
 
 import org.junit.jupiter.api.Test;
 
 import java.util.List;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-class SimpleIssueAwareTextTest {
+import static org.junit.jupiter.api.Assertions.*;
 
+class SimpleThreatAwareSystemTest {
   @Test
-  void shouldFilterByStartOffset() {
+  void shouldFilterByThreatType() {
     //given
-    SimpleIssue spellingIssue = new SimpleIssue(IssuePosition.of(4, 5), IssueType.SPELLING);
-    SimpleIssue grammarIssue = new SimpleIssue(IssuePosition.of(8, 12), IssueType.GRAMMAR);
-    List<Issue> issues = List.of(spellingIssue, grammarIssue);
+    Threat rootkit = new SimpleThreat(ThreatType.ROOTKIT, 1, "Simple-Rootkit");
+    Threat trojan = new SimpleThreat(ThreatType.TROJAN, 2, "Simple-Trojan");
+    List<Threat> threats = List.of(rootkit, trojan);
 
-    SimpleIssueAwareText simpleIssueWiseText = new SimpleIssueAwareText("I mihgt gone there", issues);
+    ThreatAwareSystem threatAwareSystem = new SimpleThreatAwareSystem("System-1", threats);
 
     //when
-    IssueAwareText filtered = simpleIssueWiseText.filtered()
-            .by(issue1 -> issue1.startOffset() == 4);
+    ThreatAwareSystem rootkitThreatAwareSystem = threatAwareSystem.filtered()
+            .by(threat -> threat.type() == ThreatType.ROOTKIT);
 
     //then
-    assertThat(filtered.issues()).hasSize(1);
-    assertThat(filtered.issues()).element(0).isEqualTo(spellingIssue);
+    assertEquals(rootkitThreatAwareSystem.threats().size(), 1);
+    assertEquals(rootkitThreatAwareSystem.threats().get(0), rootkit);
   }
-
-}
+}
\ No newline at end of file