diff --git a/src/main/java/com/example/tankbattle/Tank.java b/src/main/java/com/example/tankbattle/Tank.java
index d99d4cc..0e6ee8b 100644
--- a/src/main/java/com/example/tankbattle/Tank.java
+++ b/src/main/java/com/example/tankbattle/Tank.java
@@ -31,6 +31,7 @@ public class Tank {
 
 
     public Tank(int x, int y, Dir dir, TankFrame tf) {
+        super();
         this.x = x;
         this.y = y;
         this.dir = dir;
diff --git a/src/main/java/com/example/tankbattle/TankFrame.java b/src/main/java/com/example/tankbattle/TankFrame.java
index cf2c304..519336d 100644
--- a/src/main/java/com/example/tankbattle/TankFrame.java
+++ b/src/main/java/com/example/tankbattle/TankFrame.java
@@ -24,7 +24,7 @@ public class TankFrame extends Frame {
         setResizable(false);
         setTitle("tank battle");
         setVisible(true);
-        addKeyListener(new MyKeyListener());
+        this.addKeyListener(new MyKeyListener());
         addWindowListener(new WindowAdapter() {
             @Override
             public void windowClosing(WindowEvent e) {
@@ -37,7 +37,7 @@ public class TankFrame extends Frame {
     @Override
     public void update(Graphics g) {
         if (offScreenImage == null) {
-            offScreenImage = createImage(GAME_WIDTH, GAME_HEIGHT);
+            offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
         }
         Graphics gOffScreen = offScreenImage.getGraphics();
         Color c = gOffScreen.getColor();
@@ -58,26 +58,27 @@ public class TankFrame extends Frame {
     }
 
 
-    public class MyKeyListener extends KeyAdapter {
+    class MyKeyListener extends KeyAdapter {
 
         boolean bL = false;
         boolean bU = false;
         boolean bR = false;
         boolean bD = false;
+
         @Override
         public void keyPressed(KeyEvent e) {
             int key = e.getKeyCode();
-            switch (key){
-                case  KeyEvent.VK_LEFT:
+            switch (key) {
+                case KeyEvent.VK_LEFT:
                     bL = true;
                     break;
-                case  KeyEvent.VK_UP:
+                case KeyEvent.VK_UP:
                     bU = true;
                     break;
-                case  KeyEvent.VK_RIGHT:
+                case KeyEvent.VK_RIGHT:
                     bR = true;
                     break;
-                case  KeyEvent.VK_DOWN:
+                case KeyEvent.VK_DOWN:
                     bD = true;
                     break;
                 default:
@@ -89,7 +90,6 @@ public class TankFrame extends Frame {
 
         @Override
         public void keyReleased(KeyEvent e) {
-            System.out.println("key released");
             int key = e.getKeyCode();
             switch (key) {
                 case KeyEvent.VK_LEFT: