Merge pull request apache#1716, unit test for AbstractConfigTest.

Author: beiwei30

dubbo-common/src/main/java/com/alibaba/dubbo/common/utils/ConfigUtils.java

@@ -158,9 +158,7 @@ public static Properties getProperties() {
     }
 
     public static void setProperties(Properties properties) {
-        if (properties != null) {
-            PROPERTIES = properties;
-        }
+        PROPERTIES = properties;
     }
 
     public static void addProperties(Properties properties) {

dubbo-config/dubbo-config-api/src/main/java/com/alibaba/dubbo/config/AbstractConfig.java

@@ -214,11 +214,11 @@ && isPrimitive(method.getReturnType())) {
                             str = URL.encode(str);
                         }
                         if (parameter != null && parameter.append()) {
-                            String pre = (String) parameters.get(Constants.DEFAULT_KEY + "." + key);
+                            String pre = parameters.get(Constants.DEFAULT_KEY + "." + key);
                             if (pre != null && pre.length() > 0) {
                                 str = pre + "," + str;
                             }
-                            pre = (String) parameters.get(key);
+                            pre = parameters.get(key);
                             if (pre != null && pre.length() > 0) {
                                 str = pre + "," + str;
                             }
@@ -387,7 +387,6 @@ protected static void checkParameterName(Map<String, String> parameters) {
             return;
         }
         for (Map.Entry<String, String> entry : parameters.entrySet()) {
-            //change by tony.chenl parameter value maybe has colon.for example napoli address
             checkNameHasSymbol(entry.getKey(), entry.getValue());
         }
     }
@@ -402,7 +401,8 @@ protected static void checkProperty(String property, String value, int maxlength
         if (pattern != null) {
             Matcher matcher = pattern.matcher(value);
             if (!matcher.matches()) {
-                throw new IllegalStateException("Invalid " + property + "=\"" + value + "\" contain illegal charactor, only digit, letter, '-', '_' and '.' is legal.");
+                throw new IllegalStateException("Invalid " + property + "=\"" + value + "\" contains illegal " +
+                        "character, only digit, letter, '-', '_' or '.' is legal.");
             }
         }
     }

dubbo-config/dubbo-config-api/src/main/java/com/alibaba/dubbo/config/AbstractInterfaceConfig.java

@@ -360,7 +360,7 @@ public String getStub() {
     }
 
     public void setStub(Boolean stub) {
-        if (local == null) {
+        if (stub == null) {
             setStub((String) null);
         } else {
             setStub(String.valueOf(stub));