Solve

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

@@ -0,0 +1,23 @@
+package core.basesyntax;
+
+public class Bulldozer extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("The truck has started to shallow digging and ditching; "
+                + "short-range transportation of material; "
+                + "spreading soil dumped from trucks; "
+                + "rough grading; "
+                + "removing trees, stumps, and boulders; "
+                + "and cleaning and leveling around loading equipment.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("The truck has stopped to shallow digging and ditching; "
+                + "short-range transportation of material; "
+                + "spreading soil dumped from trucks; "
+                + "rough grading; "
+                + "removing trees, stumps, and boulders; "
+                + "and cleaning and leveling around loading equipment.");
+    }
+}

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

@@ -0,0 +1,15 @@
+package core.basesyntax;
+
+public class Excavator extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("The excavator has started digging trenches "
+                + "and breaking holes to lifting away waste and excavating mines.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("The excavator has stopped digging trenches "
+                + "and breaking holes to lifting away waste and excavating mines.");
+    }
+}

src/main/java/core/basesyntax/Machine.java

@@ -0,0 +1,7 @@
+package core.basesyntax;
+
+public abstract class Machine {
+    public abstract void doWork();
+
+    public abstract void stopWork();
+}

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

@@ -1,5 +1,16 @@
 package core.basesyntax;
 
 public class MainApp {
+    public static void main(String[] args) {
+        Machine excavator = new Excavator();
+        Machine truck = new Truck();
+        Machine bulldozer = new Bulldozer();
+        Machine[] machines = {excavator, truck, bulldozer};
+
+        for (Machine machine : machines) {
+            machine.doWork();
+            machine.stopWork();
+        }
+    }
 
 }

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

@@ -0,0 +1,15 @@
+package core.basesyntax;
+
+public class Truck extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("The truck has started to transport freight,"
+                + " carry specialized payloads, or perform other utilitarian work.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("The truck has stopped to transport freight,"
+                + " carry specialized payloads and perform other utilitarian work.");
+    }
+}