diff --git a/.idea/checkstyle-idea.xml b/.idea/checkstyle-idea.xml
deleted file mode 100644
index f0c4984..0000000
--- a/.idea/checkstyle-idea.xml
+++ /dev/null
@@ -1,16 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="CheckStyle-IDEA" serialisationVersion="2">
-    <checkstyleVersion>10.12.2</checkstyleVersion>
-    <scanScope>JavaOnly</scanScope>
-    <copyLibs>true</copyLibs>
-    <option name="thirdPartyClasspath" />
-    <option name="activeLocationIds" />
-    <option name="locations">
-      <list>
-        <ConfigurationLocation id="bundled-sun-checks" type="BUNDLED" scope="All" description="Sun Checks">(bundled)</ConfigurationLocation>
-        <ConfigurationLocation id="bundled-google-checks" type="BUNDLED" scope="All" description="Google Checks">(bundled)</ConfigurationLocation>
-      </list>
-    </option>
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/jpa-buddy.xml b/.idea/jpa-buddy.xml
deleted file mode 100644
index 966d5f5..0000000
--- a/.idea/jpa-buddy.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="JpaBuddyIdeaProjectConfig">
-    <option name="renamerInitialized" value="true" />
-  </component>
-</project>
\ No newline at end of file
diff --git a/CONTACT.md b/CONTACT.md
index 3e05c61..1e4480b 100644
--- a/CONTACT.md
+++ b/CONTACT.md
@@ -22,6 +22,8 @@
 
 ![](https://cdn.ossez.com/img/cwikius/cwikus-qr-toutiao.png)
 
+![](https://cdn.ossez.com/img/sharkfly/baidu/baidu-qr.jpg)
+
 ## 知乎
 请关注我们的知乎：https://www.zhihu.com/people/huyuchengus
 
diff --git a/cwikius-docs.iml b/cwikius-docs.iml
index 8021953..ad3c0a3 100644
--- a/cwikius-docs.iml
+++ b/cwikius-docs.iml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<module type="WEB_MODULE" version="4">
+<module type="PYTHON_MODULE" version="4">
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$" />
diff --git a/java/core/_README.md b/java/core/_README.md
index 2061365..be0c66e 100644
--- a/java/core/_README.md
+++ b/java/core/_README.md
@@ -9,3 +9,5 @@
 [](core-java-numbers.md ':include')
 
 [](core-java-strings.md ':include')
+
+[](core-java-uuid.md ':include')
\ No newline at end of file
diff --git a/java/core/core-java-uuid.md b/java/core/core-java-uuid.md
new file mode 100644
index 0000000..40c2236
--- /dev/null
+++ b/java/core/core-java-uuid.md
@@ -0,0 +1,7 @@
+## Java UUID
+
+- [在 Java 中生成只有数组和字母的 UUID](https://www.isharkfly.com/t/java-uuid/15097)
+- [Guide to UUID in Java](http://www.baeldung.com/java-uuid)
+- [Validate UUID String in Java](https://www.baeldung.com/java-validate-uuid-string)
+- [Generate the Same UUID From a String in Java](https://www.baeldung.com/java-generate-same-uuid-from-string)
+- [Generating Time Based UUIDs](https://www.baeldung.com/java-generating-time-based-uuids)