Erik Loskorikh done

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

@@ -1,2 +1,14 @@
-package core.basesyntax;public class Bulldozer {
+package core.basesyntax;
+
+public class Bulldozer extends Machine {
+
+    @Override
+    public void doWork() {
+        System.out.println("Bulldozer started work.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Bulldozer stopped work.\n");
+    }
 }

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

@@ -1,2 +1,13 @@
-package core.basesyntax;public class Excavator {
+package core.basesyntax;
+
+public class Excavator extends Machine{
+    @Override
+    public void doWork() {
+        System.out.println("Excavator started work.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Excavator stopped work.\n");
+    }
 }

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

@@ -1,2 +1,7 @@
-package core.basesyntax;public class Machine {
+package core.basesyntax;
+
+public abstract class Machine {
+    public abstract void doWork();
+
+    public abstract void stopWork();
 }

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

@@ -1,5 +1,11 @@
 package core.basesyntax;
 
 public class MainApp {
-
+    public static void main(String[] args) {
+        Machine[] machines = {new Bulldozer(), new Excavator(), new Truck()};
+        for (Machine m : machines) {
+            m.doWork();
+            m.stopWork();
+        }
+    }
 }

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

@@ -1,2 +1,13 @@
-package core.basesyntax;public class Truck {
+package core.basesyntax;
+
+public class Truck extends Machine{
+    @Override
+    public void doWork() {
+        System.out.println("Truck started work.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Truck stopped work.\n");
+    }
 }