diff --git a/pom.xml b/pom.xml
index 6eb26319a..d97d7e348 100644
--- a/pom.xml
+++ b/pom.xml
@@ -9,7 +9,7 @@
     <version>1.0-SNAPSHOT</version>
 
     <properties>
-        <jdk.version>17</jdk.version>
+        <jdk.version>11</jdk.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <maven.checkstyle.plugin.version>3.1.1</maven.checkstyle.plugin.version>
diff --git a/src/main/java/core/basesyntax/MainApp.java b/src/main/java/core/basesyntax/MainApp.java
index f99e9a019..1ec86d224 100644
--- a/src/main/java/core/basesyntax/MainApp.java
+++ b/src/main/java/core/basesyntax/MainApp.java
@@ -1,5 +1,17 @@
 package core.basesyntax;
 
+import core.basesyntax.models.Bulldozer;
+import core.basesyntax.models.Excavator;
+import core.basesyntax.models.Machine;
+import core.basesyntax.models.Truck;
+
 public class MainApp {
+    public static void main(String[] args) {
+        Machine[] machines = new Machine[] {new Bulldozer(), new Excavator(), new Truck()};
 
+        for (Machine machine : machines) {
+            machine.doWork();
+            machine.stopWork();
+        }
+    }
 }
diff --git a/src/main/java/core/basesyntax/models/Bulldozer.java b/src/main/java/core/basesyntax/models/Bulldozer.java
new file mode 100644
index 000000000..a433407f1
--- /dev/null
+++ b/src/main/java/core/basesyntax/models/Bulldozer.java
@@ -0,0 +1,13 @@
+package core.basesyntax.models;
+
+public class Bulldozer extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("Bulldozer started its work");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Bulldozer stopped working");
+    }
+}
diff --git a/src/main/java/core/basesyntax/models/Excavator.java b/src/main/java/core/basesyntax/models/Excavator.java
new file mode 100644
index 000000000..4454853e7
--- /dev/null
+++ b/src/main/java/core/basesyntax/models/Excavator.java
@@ -0,0 +1,13 @@
+package core.basesyntax.models;
+
+public class Excavator extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("Excavator started its work");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Excavator stopped working");
+    }
+}
diff --git a/src/main/java/core/basesyntax/models/Machine.java b/src/main/java/core/basesyntax/models/Machine.java
new file mode 100644
index 000000000..a1eb53b8b
--- /dev/null
+++ b/src/main/java/core/basesyntax/models/Machine.java
@@ -0,0 +1,7 @@
+package core.basesyntax.models;
+
+public abstract class Machine {
+    public abstract void doWork();
+
+    public abstract void stopWork();
+}
diff --git a/src/main/java/core/basesyntax/models/Truck.java b/src/main/java/core/basesyntax/models/Truck.java
new file mode 100644
index 000000000..ffa84eacc
--- /dev/null
+++ b/src/main/java/core/basesyntax/models/Truck.java
@@ -0,0 +1,13 @@
+package core.basesyntax.models;
+
+public class Truck extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("Truck started its work");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Truck stopped working");
+    }
+}