3 files changed, 12 insertions, 3 deletions
diff --git a/src/org/traccar/helper/ChannelBufferTools.java b/src/org/traccar/helper/ChannelBufferTools.java
index e42956228..dd63a0c86 100644
--- a/src/org/traccar/helper/ChannelBufferTools.java
+++ b/src/org/traccar/helper/ChannelBufferTools.java
@@ -19,7 +19,10 @@ import org.jboss.netty.buffer.ChannelBuffer;
 
 import java.util.Formatter;
 
-public class ChannelBufferTools {
+public final class ChannelBufferTools {
+
+    private ChannelBufferTools() {
+    }
 
     public static Integer find(ChannelBuffer buf, int start, String subString) {
         return find(buf, start, buf.readerIndex() + buf.readableBytes(), subString);
diff --git a/src/org/traccar/helper/PatternUtil.java b/src/org/traccar/helper/PatternUtil.java
index 4fa212200..184e6b31b 100644
--- a/src/org/traccar/helper/PatternUtil.java
+++ b/src/org/traccar/helper/PatternUtil.java
@@ -19,7 +19,10 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
-public class PatternUtil {
+public final class PatternUtil {
+
+    private PatternUtil() {
+    }
 
     public static String checkPattern(String pattern, String input) {
 
diff --git a/src/org/traccar/helper/UnitsConverter.java b/src/org/traccar/helper/UnitsConverter.java
index e490f366c..fe42d9ee2 100644
--- a/src/org/traccar/helper/UnitsConverter.java
+++ b/src/org/traccar/helper/UnitsConverter.java
@@ -15,7 +15,10 @@
  */
 package org.traccar.helper;
 
-public class UnitsConverter {
+public final class UnitsConverter {
+
+    private UnitsConverter() {
+    }
 
     public static double knotsFromKph(double value) { // km/h
         return value * 0.539957;