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/Bulldozer.java b/src/main/java/core/basesyntax/Bulldozer.java
new file mode 100644
index 000000000..604809a69
--- /dev/null
+++ b/src/main/java/core/basesyntax/Bulldozer.java
@@ -0,0 +1,14 @@
+package core.basesyntax;
+
+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/Excavator.java b/src/main/java/core/basesyntax/Excavator.java
new file mode 100644
index 000000000..d10d13a11
--- /dev/null
+++ b/src/main/java/core/basesyntax/Excavator.java
@@ -0,0 +1,14 @@
+package core.basesyntax;
+
+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/Machine.java b/src/main/java/core/basesyntax/Machine.java
new file mode 100644
index 000000000..5b8bb3eb3
--- /dev/null
+++ b/src/main/java/core/basesyntax/Machine.java
@@ -0,0 +1,8 @@
+package core.basesyntax;
+
+public abstract class Machine {
+
+    public abstract void doWork();
+
+    public abstract void stopWork();
+}
diff --git a/src/main/java/core/basesyntax/MainApp.java b/src/main/java/core/basesyntax/MainApp.java
index f99e9a019..1f9f7f417 100644
--- a/src/main/java/core/basesyntax/MainApp.java
+++ b/src/main/java/core/basesyntax/MainApp.java
@@ -1,5 +1,12 @@
 package core.basesyntax;
 
 public class MainApp {
+    public static void main(String[] args) {
+        Machine[] machines = new Machine[] { new Truck(), new Bulldozer(), new Excavator() };
 
+        for (Machine machine : machines) {
+            machine.doWork();
+            machine.stopWork();
+        }
+    }
 }
diff --git a/src/main/java/core/basesyntax/Truck.java b/src/main/java/core/basesyntax/Truck.java
new file mode 100644
index 000000000..894531285
--- /dev/null
+++ b/src/main/java/core/basesyntax/Truck.java
@@ -0,0 +1,14 @@
+package core.basesyntax;
+
+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.");
+    }
+}