diff --git a/src/main/java/org/cafesip/sipunit/EventSubscriber.java b/src/main/java/org/cafesip/sipunit/EventSubscriber.java
index 10e09cbbf4..91e12ca369 100644
--- a/src/main/java/org/cafesip/sipunit/EventSubscriber.java
+++ b/src/main/java/org/cafesip/sipunit/EventSubscriber.java
@@ -369,7 +369,7 @@ protected Request createRequestMessage(String method, int duration, String event
       AddressFactory addrFactory = parent.getAddressFactory();
       HeaderFactory hdrFactory = parent.getHeaderFactory();
 
-      Request req = null;
+      Request req;
 
       if (dialog == null) {
         // first time sending a request
diff --git a/src/main/java/org/cafesip/sipunit/MessageDigestAlgorithm.java b/src/main/java/org/cafesip/sipunit/MessageDigestAlgorithm.java
index 800a7a7441..e378f397d2 100644
--- a/src/main/java/org/cafesip/sipunit/MessageDigestAlgorithm.java
+++ b/src/main/java/org/cafesip/sipunit/MessageDigestAlgorithm.java
@@ -72,7 +72,7 @@ public static String calculateResponse(String algorithm, String username_value,
 
     // The following follows closely the algorithm for generating a response
     // digest as specified by rfc2617
-    String A1 = null;
+    String A1;
 
     if (algorithm == null || algorithm.trim().length() == 0
         || algorithm.trim().equalsIgnoreCase("MD5")) {
@@ -86,7 +86,7 @@ public static String calculateResponse(String algorithm, String username_value,
               + cnonce_value;
     }
 
-    String A2 = null;
+    String A2;
     if (qop_value == null || qop_value.trim().length() == 0
         || qop_value.trim().equalsIgnoreCase("auth")) {
       A2 = Method + ":" + digest_uri_value;
@@ -96,7 +96,7 @@ public static String calculateResponse(String algorithm, String username_value,
       A2 = Method + ":" + digest_uri_value + ":" + H(entity_body);
     }
 
-    String request_digest = null;
+    String request_digest;
     if (cnonce_value != null && qop_value != null
         && (qop_value.equals("auth") || (qop_value.equals("auth-int")))) {
       request_digest =
diff --git a/src/main/java/org/cafesip/sipunit/SipCall.java b/src/main/java/org/cafesip/sipunit/SipCall.java
index 30418e4ffc..2436ebd53d 100644
--- a/src/main/java/org/cafesip/sipunit/SipCall.java
+++ b/src/main/java/org/cafesip/sipunit/SipCall.java
@@ -1280,7 +1280,7 @@ public boolean respondToReinvite(SipTransaction siptrans, int statusCode, String
     initErrorInfo();
 
     try {
-      ContactHeader contact_hdr = null;
+      ContactHeader contact_hdr;
       if (newContact == null) {
         contact_hdr = (ContactHeader) parent.getContactInfo().getContactHeader().clone();
       } else {
diff --git a/src/main/java/org/cafesip/sipunit/SipSession.java b/src/main/java/org/cafesip/sipunit/SipSession.java
index 89728d2255..1cc2aeb5d1 100644
--- a/src/main/java/org/cafesip/sipunit/SipSession.java
+++ b/src/main/java/org/cafesip/sipunit/SipSession.java
@@ -441,7 +441,7 @@ public void processResponse(ResponseEvent response) {
       return;
     }
 
-    SipTransaction sip_trans = null;
+    SipTransaction sip_trans;
 
     synchronized (respTransactions) {
       sip_trans = (SipTransaction) respTransactions.get(trans);
@@ -480,7 +480,7 @@ public void processTimeout(TimeoutEvent timeout) {
       return;
     }
 
-    SipTransaction sip_trans = null;
+    SipTransaction sip_trans;
     synchronized (respTransactions) {
       sip_trans = (SipTransaction) respTransactions.get(trans);
     }
@@ -1688,7 +1688,7 @@ public boolean sendUnidirectionalResponse(RequestEvent request, int statusCode,
 
   public AuthorizationHeader getAuthorization(String method, String uri, String requestBody,
       WWWAuthenticateHeader authHeader, String username, String password) throws SecurityException {
-    String response = null;
+    String response;
     try {
       response = MessageDigestAlgorithm.calculateResponse(authHeader.getAlgorithm(), username,
           authHeader.getRealm(), new String(password), authHeader.getNonce(),
@@ -1701,7 +1701,7 @@ public AuthorizationHeader getAuthorization(String method, String uri, String re
           "The received authenticate header was malformatted: " + exc.getMessage());
     }
 
-    AuthorizationHeader authorization = null;
+    AuthorizationHeader authorization;
     try {
       if (authHeader instanceof ProxyAuthenticateHeader) {
         authorization =
diff --git a/src/main/java/org/cafesip/sipunit/SipStack.java b/src/main/java/org/cafesip/sipunit/SipStack.java
index a1714bdc77..f5e1cc8c64 100644
--- a/src/main/java/org/cafesip/sipunit/SipStack.java
+++ b/src/main/java/org/cafesip/sipunit/SipStack.java
@@ -85,7 +85,7 @@ public class SipStack implements SipListener {
   private static final Properties defaultProperties = new Properties();
 
   static {
-    String host = null;
+    String host;
     try {
       host = InetAddress.getLocalHost().getHostAddress();
     } catch (UnknownHostException e) {
diff --git a/src/test/java/org/cafesip/sipunit/test/proxynoauth/ExampleTestWithProxyNoAuth.java b/src/test/java/org/cafesip/sipunit/test/proxynoauth/ExampleTestWithProxyNoAuth.java
index fae64dfb64..b6c80eb93d 100644
--- a/src/test/java/org/cafesip/sipunit/test/proxynoauth/ExampleTestWithProxyNoAuth.java
+++ b/src/test/java/org/cafesip/sipunit/test/proxynoauth/ExampleTestWithProxyNoAuth.java
@@ -69,7 +69,7 @@ public class ExampleTestWithProxyNoAuth {
   private static final Properties defaultProperties = new Properties();
 
   static {
-    String host = null;
+    String host;
     try {
       host = InetAddress.getLocalHost().getHostAddress();
     } catch (UnknownHostException e) {
diff --git a/src/test/java/org/cafesip/sipunit/test/util/AuthUtil.java b/src/test/java/org/cafesip/sipunit/test/util/AuthUtil.java
index 01552371ba..9cee395344 100644
--- a/src/test/java/org/cafesip/sipunit/test/util/AuthUtil.java
+++ b/src/test/java/org/cafesip/sipunit/test/util/AuthUtil.java
@@ -22,7 +22,7 @@ public class AuthUtil {
    */
   public static WWWAuthenticateHeader getAuthenticationHeader(SipRequest message,
       HeaderFactory headerFactory, String realm) throws Exception {
-    WWWAuthenticateHeader header = null;
+    WWWAuthenticateHeader header;
     String htype =
         message.getRequestEvent().getRequest().getMethod().equals(Request.REGISTER) == true ? WWWAuthenticateHeader.NAME
             : ProxyAuthenticateHeader.NAME;