diff --git a/tools/cooja/java/se/sics/cooja/util/StringUtils.java b/tools/cooja/java/se/sics/cooja/util/StringUtils.java
new file mode 100644
index 000000000..44afa88de
--- /dev/null
+++ b/tools/cooja/java/se/sics/cooja/util/StringUtils.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2009, Swedish Institute of Computer Science. All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. Redistributions in
+ * binary form must reproduce the above copyright notice, this list of
+ * conditions and the following disclaimer in the documentation and/or other
+ * materials provided with the distribution. 3. Neither the name of the
+ * Institute nor the names of its contributors may be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $Id: StringUtils.java,v 1.1 2009/04/20 17:14:19 nifi Exp $
+ */
+
+package se.sics.cooja.util;
+
+/**
+ * Some utility methods for generating hex dumps.
+ *
+ * @author Niclas Finne
+ */
+public class StringUtils {
+
+  private static final char[] HEX = {
+    '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
+  };
+
+  private StringUtils() {
+    // Prevent instances of this class
+  }
+
+  public static String toHex(byte[] data) {
+    char[] buf = new char[data.length * 2];
+    for (int i = 0, j = 0, n = data.length; i < n; i++, j += 2) {
+      buf[j] = HEX[(data[i] >> 4) & 0xf];
+      buf[j + 1] = HEX[data[i] & 0xf];
+    }
+    return new String(buf);
+  }
+
+  public static String toHex(byte[] data, int bytesPerGroup) {
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0, n = data.length; i < n; i++) {
+      if ((i % bytesPerGroup) == 0 && i > 0) {
+        sb.append(' ');
+      }
+      sb.append(HEX[(data[i] >> 4) & 0xf]);
+      sb.append(HEX[data[i] & 0xf]);
+    }
+    return sb.toString();
+  }
+
+  public static String hexDump(byte[] data) {
+    return hexDump(data, 5, 4);
+  }
+
+  public static String hexDump(byte[] data, int groupsPerLine, int bytesPerGroup) {
+    if (bytesPerGroup <= 0) {
+      throw new IllegalArgumentException("0 bytes per group");
+    }
+    if (groupsPerLine <= 0) {
+      groupsPerLine = 1;
+    }
+    final int bytesPerLine = groupsPerLine * bytesPerGroup;
+    StringBuilder sb = new StringBuilder();
+    for (int j = 0; j < data.length; j += bytesPerLine) {
+      int n = data.length - j;
+      if (n > bytesPerLine) {
+        n = bytesPerLine;
+      }
+      for (int i = 0; i < bytesPerLine; i++) {
+        if ((i % bytesPerGroup) == 0 && i > 0) {
+          sb.append(' ');
+        }
+        if (i < n) {
+          sb.append(HEX[(data[j + i] >> 4) & 0xf]);
+          sb.append(HEX[data[j + i] & 0xf]);
+        } else {
+          sb.append("  ");
+        }
+      }
+      sb.append("  ");
+      for (int i = 0; i < n; i++) {
+        if (data[j + i] > 32) {
+          sb.append((char)(data[j + i] & 0xff));
+        } else {
+          sb.append('.');
+        }
+      }
+      sb.append('\n');
+    }
+    return sb.toString();
+  }
+
+}