diff --git a/src/main/java/de/neemann/digital/draw/graphics/GraphicSVG.java b/src/main/java/de/neemann/digital/draw/graphics/GraphicSVG.java
index 46d38b8de..eca7c7fe9 100644
--- a/src/main/java/de/neemann/digital/draw/graphics/GraphicSVG.java
+++ b/src/main/java/de/neemann/digital/draw/graphics/GraphicSVG.java
@@ -94,6 +94,8 @@ public class GraphicSVG implements Graphic, Closeable {
     @Override
     public void drawPolygon(Polygon p, Style style) {
         try {
+            //modification of loop variable i is intended!
+            //CHECKSTYLE.OFF: ModifiedControlVariable
             w.write("<path d=\"M " + str(p.get(0)));
             for (int i = 1; i < p.size(); i++)
                 if (p.isBezierStart(i)) {
@@ -101,6 +103,7 @@ public class GraphicSVG implements Graphic, Closeable {
                     i += 2;
                 } else
                     w.write(" L " + str(p.get(i)));
+            //CHECKSTYLE.ON: ModifiedControlVariable
 
             if (p.isClosed())
                 w.write(" Z");
diff --git a/src/main/java/de/neemann/digital/draw/graphics/GraphicSwing.java b/src/main/java/de/neemann/digital/draw/graphics/GraphicSwing.java
index 57f1caa5f..0e9e1aa76 100644
--- a/src/main/java/de/neemann/digital/draw/graphics/GraphicSwing.java
+++ b/src/main/java/de/neemann/digital/draw/graphics/GraphicSwing.java
@@ -51,6 +51,8 @@ public class GraphicSwing implements Graphic {
     public void drawPolygon(Polygon p, Style style) {
         applyStyle(style);
         Path2D path = new GeneralPath();
+        //modification of loop variable i is intended!
+        //CHECKSTYLE.OFF: ModifiedControlVariable
         for (int i = 0; i < p.size(); i++) {
             if (i == 0) {
                 path.moveTo(p.get(i).x, p.get(i).y);
@@ -62,6 +64,7 @@ public class GraphicSwing implements Graphic {
                     path.lineTo(p.get(i).x, p.get(i).y);
             }
         }
+        //CHECKSTYLE.ON: ModifiedControlVariable
 
         if (p.isClosed())
             path.closePath();
diff --git a/src/main/java/de/neemann/digital/draw/model/NetList.java b/src/main/java/de/neemann/digital/draw/model/NetList.java
index f7e709613..b5b9887ee 100644
--- a/src/main/java/de/neemann/digital/draw/model/NetList.java
+++ b/src/main/java/de/neemann/digital/draw/model/NetList.java
@@ -46,6 +46,8 @@ public class NetList implements Iterable<Net> {
         mergeLabels();
     }
 
+    //modification of loop variable j is intended!
+    //CHECKSTYLE.OFF: ModifiedControlVariable
     private void mergeLabels() {
         for (int i = 0; i < netList.size() - 1; i++)
             for (int j = i + 1; j < netList.size(); j++)
@@ -55,6 +57,7 @@ public class NetList implements Iterable<Net> {
                     j--;
                 }
     }
+    //CHECKSTYLE.ON: ModifiedControlVariable
 
     /**
      * Creates a copy of the given net list