update wording for full util option

Author: wing328

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractJavaCodegen.java

@@ -96,7 +96,7 @@ public AbstractJavaCodegen() {
         cliOptions.add(CliOption.newBoolean(CodegenConstants.SERIALIZABLE_MODEL, CodegenConstants.SERIALIZABLE_MODEL_DESC));
         cliOptions.add(CliOption.newBoolean(CodegenConstants.SERIALIZE_BIG_DECIMAL_AS_STRING, CodegenConstants
                 .SERIALIZE_BIG_DECIMAL_AS_STRING_DESC));
-        cliOptions.add(CliOption.newBoolean(FULL_JAVA_UTIL, "whether to use fully qualified name for classes under java.util"));
+        cliOptions.add(CliOption.newBoolean(FULL_JAVA_UTIL, "whether to use fully qualified name for classes under java.util. This option only works for Java API client"));
         cliOptions.add(new CliOption("hideGenerationTimestamp", "hides the timestamp when files were generated"));
 
         CliOption dateLibrary = new CliOption(DATE_LIBRARY, "Option. Date library to use");