diff --git a/p3c-pmd/src/main/resources/rulesets/java/ali-concurrent.xml b/p3c-pmd/src/main/resources/rulesets/java/ali-concurrent.xml
index 0f8b988..7733a56 100644
--- a/p3c-pmd/src/main/resources/rulesets/java/ali-concurrent.xml
+++ b/p3c-pmd/src/main/resources/rulesets/java/ali-concurrent.xml
@@ -116,8 +116,10 @@ Positive example 3：
         <example>
             <![CDATA[
     public class TimerTaskThread extends Thread {
-        public TimerTaskThread(){
-        super.setName("TimerTaskThread"); …
+        public TimerTaskThread() {
+            super.setName("TimerTaskThread");
+            // do something
+        }
     }
        ]]>
         </example>
@@ -134,9 +136,9 @@ Positive example 3：
             <![CDATA[
 Positive example 1：
     private static final String FORMAT = "yyyy-MM-dd HH:mm:ss";
-    public String getFormat(Date date){
+    public String getFormat(Date date) {
         SimpleDateFormat dateFormat = new SimpleDateFormat(FORMAT);
-        return sdf.format(date);
+        return dateFormat.format(date);
     }
         ]]>
         </example>
@@ -144,10 +146,11 @@ Positive example 1：
             <![CDATA[
 Positive example 2：
     private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-    public void getFormat(){
-        synchronized (sdf){
-        sdf.format(new Date());
-        ….;
+    public void getFormat() {
+        synchronized(SIMPLE_DATE_FORMAT) {
+            SIMPLE_DATE_FORMAT.format(new Date());
+            // do something
+        }
     }
         ]]>
         </example>