diff --git a/src/main/java/core/basesyntax/Bulldozer.java b/src/main/java/core/basesyntax/Bulldozer.java
index 99984d502..f1d2d2c49 100644
--- a/src/main/java/core/basesyntax/Bulldozer.java
+++ b/src/main/java/core/basesyntax/Bulldozer.java
@@ -2,12 +2,12 @@
 
 public class Bulldozer extends Machine {
     @Override
-    public String doWork() {
-        return "Bulldozer started its work.";
+    public void doWork() {
+        System.out.println("Bulldozer started its work.");
     }
 
     @Override
-    public String stopWork() {
-        return "Bulldozer stopped its work.";
+    public void stopWork() {
+        System.out.println("Bulldozer stopped its work.");
     }
 }
diff --git a/src/main/java/core/basesyntax/Excavator.java b/src/main/java/core/basesyntax/Excavator.java
index 3db99f927..fbf5f6122 100644
--- a/src/main/java/core/basesyntax/Excavator.java
+++ b/src/main/java/core/basesyntax/Excavator.java
@@ -2,12 +2,12 @@
 
 public class Excavator extends Machine {
     @Override
-    public String doWork() {
-        return "Excavator started its work.";
+    public void doWork() {
+        System.out.println("Excavator started its work.");
     }
 
     @Override
-    public String stopWork() {
-        return "Excavator stopped its work.";
+    public void stopWork() {
+        System.out.println("Excavator stopped its work.");
     }
 }
diff --git a/src/main/java/core/basesyntax/Machine.java b/src/main/java/core/basesyntax/Machine.java
index 576b6fb49..4219699a5 100644
--- a/src/main/java/core/basesyntax/Machine.java
+++ b/src/main/java/core/basesyntax/Machine.java
@@ -1,7 +1,7 @@
 package core.basesyntax;
 
 public abstract class Machine {
-    public abstract String doWork();
+    public abstract void doWork();
 
-    public abstract String stopWork();
+    public abstract void stopWork();
 }
diff --git a/src/main/java/core/basesyntax/MainApp.java b/src/main/java/core/basesyntax/MainApp.java
index 7a55d6502..a91189c38 100644
--- a/src/main/java/core/basesyntax/MainApp.java
+++ b/src/main/java/core/basesyntax/MainApp.java
@@ -4,8 +4,8 @@ public class MainApp {
     public static void main(String[] args) {
         Machine[] machines = {new Bulldozer(), new Excavator(), new Truck()};
         for (Machine machine : machines) {
-            System.out.println(machine.doWork());
-            System.out.println(machine.stopWork());
+            machine.doWork();
+            machine.stopWork();
         }
     }
 }
diff --git a/src/main/java/core/basesyntax/Truck.java b/src/main/java/core/basesyntax/Truck.java
index c63d7f440..3c4db370c 100644
--- a/src/main/java/core/basesyntax/Truck.java
+++ b/src/main/java/core/basesyntax/Truck.java
@@ -2,12 +2,12 @@
 
 public class Truck extends Machine {
     @Override
-    public String doWork() {
-        return "Truck started its work.";
+    public void doWork() {
+        System.out.println("Truck started its work.");
     }
 
     @Override
-    public String stopWork() {
-        return "Truck stopped its work.";
+    public void stopWork() {
+        System.out.println("Truck stopped its work.");
     }
 }