First solution

pom.xml

@@ -47,6 +47,15 @@
                     <linkXRef>false</linkXRef>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>23</source>
+                    <target>23</target>
+                    <compilerArgs>--enable-preview</compilerArgs>
+                </configuration>
+            </plugin>
         </plugins>
         <pluginManagement>
             <plugins>

src/main/java/core/basesyntax/Bulldozer.java

@@ -0,0 +1,13 @@
+package core.basesyntax;
+
+public abstract class Bulldozer extends Machine {
+
+    @Override
+    public void doWork() {
+        System.out.println("The buldozer is working");
+    }
+    @Override
+    public void stopWork() {
+        System.out.println("The buldozer is not working");
+    }
+}

src/main/java/core/basesyntax/Excavator.java

@@ -0,0 +1,13 @@
+package core.basesyntax;
+
+public abstract class Excavator extends Machine {
+
+    @Override
+    public void doWork() {
+        System.out.println("The excavator is working");
+    }
+    @Override
+    public void stopWork() {
+        System.out.println("The truck is not working");
+    }
+}

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(); {}
+}

src/main/java/core/basesyntax/MainApp.java

@@ -1,9 +1,24 @@
 package core.basesyntax;
 
 public class MainApp {
-
     public static void main(String[] args) {
-
         System.out.println("First solution");
+
+        Machine truck = new Truck() {
+        };
+        Machine bulldozer = new Bulldozer() {
+        };
+        Machine excavator = new Excavator() {
+        };
+
+
+        Machine[] machines = new Machine[3];
+        machines = (truck, bulldozer, excavator)
+
+        for (Machine machine : machines) {
+            machine.doWork();
+            machine.stopWork();
+        }
+
     }
 }

src/main/java/core/basesyntax/Truck.java

@@ -0,0 +1,13 @@
+package core.basesyntax;
+
+public abstract class Truck extends Machine {
+
+    @Override
+    public void doWork() {
+        System.out.println("The truck is working" );
+    }
+    @Override
+    public void stopWork() {
+        System.out.println("The truck is not working");
+    }
+}

src/test/java/core/basesyntax/MainAppTest.java

@@ -2,4 +2,6 @@
 
 public class MainAppTest {
 
+
+
 }