StringBuffer -> StringBuilder

Change-Id: Ibacf9357619712909544ddeb901bbef04c822bfe
diff --git a/utils/misc/src/main/java/org/onlab/packet/Ethernet.java b/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
index 09a79f5..0b41457 100644
--- a/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
+++ b/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
@@ -585,7 +585,7 @@
     @Override
     public String toString() {
 
-        final StringBuffer sb = new StringBuffer("\n");
+        final StringBuilder sb = new StringBuilder("\n");
 
         final IPacket pkt = this.getPayload();
 
diff --git a/utils/misc/src/main/java/org/onlab/packet/IPv4.java b/utils/misc/src/main/java/org/onlab/packet/IPv4.java
index b8b58bc..95695dc 100644
--- a/utils/misc/src/main/java/org/onlab/packet/IPv4.java
+++ b/utils/misc/src/main/java/org/onlab/packet/IPv4.java
@@ -511,7 +511,7 @@
      * @return string form of ip address
      */
     public static String fromIPv4Address(final int ipAddress) {
-        final StringBuffer sb = new StringBuffer();
+        final StringBuilder sb = new StringBuilder();
         int result = 0;
         for (int i = 0; i < 4; ++i) {
             result = ipAddress >> (3 - i) * 8 & 0xff;
@@ -537,7 +537,7 @@
         if (ipAddresses == null) {
             return "null";
         }
-        final StringBuffer sb = new StringBuffer();
+        final StringBuilder sb = new StringBuilder();
         sb.append("[");
         for (final Integer ip : ipAddresses) {
             sb.append(IPv4.fromIPv4Address(ip));
diff --git a/utils/misc/src/main/java/org/onlab/packet/IpAddress.java b/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
index 10ccf8f..75b5b2f 100644
--- a/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
+++ b/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
@@ -537,7 +537,7 @@
      */
     private String ipv6ToStringHelper() {
         //Populate a buffer with the string of the full address with leading zeros stripped
-        StringBuffer buff = new StringBuffer();
+        StringBuilder buff = new StringBuilder();
         buff.append(String.format("%x:%x:%x:%x:%x:%x:%x:%x",
                 (((octets[0] & BIT_MASK) << 8) | (octets[1] & BIT_MASK)),
                 (((octets[2] & BIT_MASK) << 8) | (octets[3] & BIT_MASK)),