diff --git a/tools/cooja/java/org/contikios/cooja/plugins/RadioLogger.java b/tools/cooja/java/org/contikios/cooja/plugins/RadioLogger.java
index 70eba23bb..546b66566 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/RadioLogger.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/RadioLogger.java
@@ -685,8 +685,8 @@ public class RadioLogger extends VisPlugin {
       return;
     }
 
-    StringBuffer brief = new StringBuffer();
-    StringBuffer verbose = new StringBuffer();
+    StringBuilder brief = new StringBuilder();
+    StringBuilder verbose = new StringBuilder();
 
     /* default analyzer */
     PacketAnalyzer.Packet packet = new PacketAnalyzer.Packet(data, PacketAnalyzer.MAC_LEVEL);
@@ -713,7 +713,7 @@ public class RadioLogger extends VisPlugin {
     }
   }
 
-  private boolean analyzePacket(PacketAnalyzer.Packet packet, StringBuffer brief, StringBuffer verbose) {
+  private boolean analyzePacket(PacketAnalyzer.Packet packet, StringBuilder brief, StringBuilder verbose) {
     if (analyzers == null) return false;
     try {
       boolean analyze = true;
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/ICMPv6Analyzer.java b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/ICMPv6Analyzer.java
index 7b1d03fd0..e5b9f3681 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/ICMPv6Analyzer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/ICMPv6Analyzer.java
@@ -39,8 +39,8 @@ public class ICMPv6Analyzer extends PacketAnalyzer {
     "ROUTER RENUMBER", "NODE INFORMATION QUERY", "NODE INFORMATION RESPONSE"};
 
   @Override
-  public int analyzePacket(Packet packet, StringBuffer brief,
-                           StringBuffer verbose) {
+  public int analyzePacket(Packet packet, StringBuilder brief,
+                           StringBuilder verbose) {
     int type = packet.get(0) & 0xff;
     int code = packet.get(1) & 0xff;
 //        int checksum = ((packet.get(2) & 0xff) << 8) | packet.get(3) & 0xff;
@@ -69,11 +69,11 @@ public class ICMPv6Analyzer extends PacketAnalyzer {
           int mop = (packet.get(8) >> 3) & 0x07;
           int dtsn = packet.get(9);
 
-          verbose.append(" InstanceID: " + instanceID
-                  + " Version: " + version
-                  + " Rank:" + rank
-                  + " MOP: " + mop
-                  + " DTSN: " + dtsn);
+          verbose.append(" InstanceID: ").append(instanceID)
+                  .append(", Version: ").append(version)
+                  .append(", Rank: ").append(rank)
+                  .append(", MOP: ").append(mop)
+                  .append(", DTSN: ").append(dtsn);
           packet.consumeBytesStart(8);
 
           break;
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IEEE802154Analyzer.java b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IEEE802154Analyzer.java
index ce94e8e14..68049c367 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IEEE802154Analyzer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IEEE802154Analyzer.java
@@ -61,7 +61,7 @@ public class IEEE802154Analyzer extends PacketAnalyzer {
    */
 
   @Override
-  public int analyzePacket(Packet packet, StringBuffer brief, StringBuffer verbose) {
+  public int analyzePacket(Packet packet, StringBuilder brief, StringBuilder verbose) {
 
     if (pcapExporter != null) {
       try {
@@ -141,14 +141,16 @@ public class IEEE802154Analyzer extends PacketAnalyzer {
 
       verbose.append("</b><br>From ");
       if (srcPanID != 0) {
-        verbose.append(StringUtils.toHex((byte) (srcPanID >> 8)))
+        verbose.append("0x")
+                .append(StringUtils.toHex((byte) (srcPanID >> 8)))
                 .append(StringUtils.toHex((byte) (srcPanID & 0xff)))
                 .append('/');
       }
       printAddress(verbose, srcAddrMode, sourceAddress);
       verbose.append(" to ");
       if (destPanID != 0) {
-        verbose.append(StringUtils.toHex((byte) (destPanID >> 8)))
+        verbose.append("0x")
+                .append(StringUtils.toHex((byte) (destPanID >> 8)))
                 .append(StringUtils.toHex((byte) (destPanID & 0xff)))
                 .append('/');
       }
@@ -169,14 +171,26 @@ public class IEEE802154Analyzer extends PacketAnalyzer {
     return ANALYSIS_OK_CONTINUE;
   }
 
-  private void printAddress(StringBuffer sb, int type, byte[] addr) {
+  private void printAddress(StringBuilder sb, int type, byte[] addr) {
     if (type == SHORT_ADDRESS) {
-      sb.append(StringUtils.toHex(addr));
+      sb.append("0x").append(StringUtils.toHex(addr));
     } else if (type == LONG_ADDRESS) {
-      sb.append(StringUtils.toHex(addr[0]) + StringUtils.toHex(addr[1]) + ":"
-              + StringUtils.toHex(addr[2]) + StringUtils.toHex(addr[3]) + ":"
-              + StringUtils.toHex(addr[4]) + StringUtils.toHex(addr[5]) + ":"
-              + StringUtils.toHex(addr[6]) + StringUtils.toHex(addr[7]));
+      sb.append(StringUtils.toHex(addr[0]))
+              .append(':')
+              .append(StringUtils.toHex(addr[1]))
+              .append(':')
+              .append(StringUtils.toHex(addr[2]))
+              .append(':')
+              .append(StringUtils.toHex(addr[3]))
+              .append(':')
+              .append(StringUtils.toHex(addr[4]))
+              .append(':')
+              .append(StringUtils.toHex(addr[5]))
+              .append(':')
+              .append(StringUtils.toHex(addr[6]))
+              .append(':')
+              .append(StringUtils.toHex(addr[7]));
+
     }
   }
 }
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPHCPacketAnalyzer.java b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPHCPacketAnalyzer.java
index 7cbb97935..2a70fea6f 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPHCPacketAnalyzer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPHCPacketAnalyzer.java
@@ -67,8 +67,8 @@ public class IPHCPacketAnalyzer extends PacketAnalyzer {
   }
 
   @Override
-  public int analyzePacket(Packet packet, StringBuffer brief,
-                           StringBuffer verbose) {
+  public int analyzePacket(Packet packet, StringBuilder brief,
+                           StringBuilder verbose) {
 
     /* if packet has less than 3 bytes it is not interesting ... */
     if (packet.size() < 3) return ANALYSIS_FAILED;
@@ -91,12 +91,18 @@ public class IPHCPacketAnalyzer extends PacketAnalyzer {
 
     /* need to decompress while analyzing - add that later... */
     verbose.append("<b>IPHC HC-06</b><br>");
-    verbose.append("tf = " + tf + " nhc = " + nhc + " hlim = " + hlim
-            + " cid = " + cid + " sac = " + sac + " sam = " + sam
-            + " MCast = " + m + " dac = " + dac + " dam = " + dam);
+    verbose.append("TF = ").append(tf)
+            .append(", NH = ").append(nhc)
+            .append(", HLIM = ").append(hlim)
+            .append(", CID = ").append(cid)
+            .append(", SAC = ").append(sac)
+            .append(", SAM = ").append(sam)
+            .append(", MCast = ").append(m)
+            .append(", DAC = ").append(dac)
+            .append(", DAM = ").append(dam);
     if (cid == 1) {
-      verbose.append("<br>Contexts: sci=" + (packet.get(2) >> 4) + " dci="
-              + (packet.get(2) & 0x0f));
+      verbose.append("<br>Contexts: sci=").append(packet.get(2) >> 4).
+              append(" dci=").append(packet.get(2) & 0x0f);
       sci = packet.get(2) >> 4;
       dci = packet.get(2) & 0x0f;
     }
@@ -412,8 +418,9 @@ public class IPHCPacketAnalyzer extends PacketAnalyzer {
     }
 
     verbose.append("<br><b>IPv6 ").append(protoStr)
-            .append("</b> TC = " + trafficClass
-            + " FL: " + flowLabel + "<br>");
+            .append("</b> TC = ").append(trafficClass)
+            .append(" FL: ").append(flowLabel)
+            .append("<br>");
     verbose.append("From ");
     printAddress(verbose, srcAddress);
     verbose.append("  to ");
@@ -431,7 +438,7 @@ public class IPHCPacketAnalyzer extends PacketAnalyzer {
     }
   }
 
-  public static void printAddress(StringBuffer out, byte[] address) {
+  public static void printAddress(StringBuilder out, byte[] address) {
     for (int i = 0; i < 16; i += 2) {
       out.append(StringUtils.toHex((byte) (address[i] & 0xff))
               + StringUtils.toHex((byte) (address[i + 1] & 0xff)));
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPv6PacketAnalyzer.java b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPv6PacketAnalyzer.java
index 0dc34896e..0d33b0bd3 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPv6PacketAnalyzer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/IPv6PacketAnalyzer.java
@@ -19,8 +19,8 @@ public class IPv6PacketAnalyzer extends PacketAnalyzer {
   }
 
   @Override
-  public int analyzePacket(Packet packet, StringBuffer brief,
-                           StringBuffer verbose) {
+  public int analyzePacket(Packet packet, StringBuilder brief,
+                           StringBuilder verbose) {
 
     /* if packet has less than 40 bytes it is not interesting ... */
     if (packet.size() < 40) return ANALYSIS_FAILED;
@@ -57,8 +57,8 @@ public class IPv6PacketAnalyzer extends PacketAnalyzer {
     packet.pos += 41;
 
     verbose.append("<br><b>IPv6 ").append(protoStr)
-            .append("</b> TC = " + trafficClass
-            + " FL: " + flowLabel + "<br>");
+            .append("</b> TC = ").append(trafficClass)
+            .append(" FL: ").append(flowLabel).append("<br>");
     verbose.append("From ");
     printAddress(verbose, srcAddress);
     verbose.append("  to ");
@@ -69,7 +69,7 @@ public class IPv6PacketAnalyzer extends PacketAnalyzer {
     return ANALYSIS_OK_CONTINUE;
   }
 
-  public static void printAddress(StringBuffer out, byte[] address) {
+  public static void printAddress(StringBuilder out, byte[] address) {
     for (int i = 0; i < 16; i += 2) {
       out.append(StringUtils.toHex((byte) (address[i] & 0xff))
               + StringUtils.toHex((byte) (address[i + 1] & 0xff)));
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/PacketAnalyzer.java b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/PacketAnalyzer.java
index 73549cce3..3be8a8284 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/analyzers/PacketAnalyzer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/analyzers/PacketAnalyzer.java
@@ -83,5 +83,5 @@ public abstract class PacketAnalyzer {
 
   public abstract boolean matchPacket(Packet packet);
 
-  public abstract int analyzePacket(Packet packet, StringBuffer brief, StringBuffer verbose);
+  public abstract int analyzePacket(Packet packet, StringBuilder brief, StringBuilder verbose);
 }