implement abstact class Machine

implements Bulldozer,Excavator,Truck;and overriding method doWork,stopWork
added psvm to MainApp

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 its work.");
+    }
+}

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

@@ -0,0 +1,13 @@
+package core.basesyntax;
+
+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 its work.");
+    }
+}

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

@@ -0,0 +1,9 @@
+package core.basesyntax;
+
+public abstract class Machine {
+
+    public abstract void doWork();
+
+    public abstract void stopWork();
+
+}

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

@@ -2,4 +2,17 @@
 
 public class MainApp {
 
+    public static void main(String[] args) {
+
+        Machine truck = new Truck();
+        Machine bulldozer = new Bulldozer();
+        Machine excavator = new Excavator();
+
+        Machine[] machines = new Machine[] {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 class Truck extends Machine {
+    @Override
+    public void doWork() {
+        System.out.println("Truck started its work.");
+    }
+
+    @Override
+    public void stopWork() {
+        System.out.println("Truck stopped its work.");
+    }
+}