diff --git a/_sidebar.md b/_sidebar.md
index 9030948..586c58f 100644
--- a/_sidebar.md
+++ b/_sidebar.md
@@ -3,9 +3,10 @@
   - [联系方式](CONTACT.md)
 
 - Java
-  - [概述和环境配置](java/index.md)
-  - [语言基础](java/fundamentals/index.md)
-  - [核心编程](java/core/index.md)
+  - [概述和环境配置](java/_README.md)
+  - [核心编程](java/core/_README.md)
+  - [语言基础](java/fundamentals/_README.md)
+  
   
 - 其他小工具
   - [JWT](jwt/README.md)
diff --git a/java/index.md b/java/_README.md
similarity index 100%
rename from java/index.md
rename to java/_README.md
diff --git a/java/core/_README.md b/java/core/_README.md
new file mode 100644
index 0000000..65fce91
--- /dev/null
+++ b/java/core/_README.md
@@ -0,0 +1,7 @@
+# Java 核心编程
+
+[](annotation.md ':include')
+
+[](core-java-8.md ':include')
+
+[](core-java-strings.md ':include')
diff --git a/java/core/annotation.md b/java/core/annotation.md
index 1b0a6ef..90f7104 100644
--- a/java/core/annotation.md
+++ b/java/core/annotation.md
@@ -1,4 +1,6 @@
-# Annotation（注解）
+## Annotation（注解）
+Java 注解（Annotation）又称 Java 标注，是 JDK5.0 引入的一种注释机制。
+
+Java 语言中的类、方法、变量、参数和包等都可以被标注。和 Javadoc 不同，Java 标注可以通过反射获取标注内容。在编译器生成类文件时，标注可以被嵌入到字节码中。Java 虚拟机可以保留标注内容，在运行时可以获取到标注内容 。 当然它也支持自定义 Java 标注。
+
 * [Java @Deprecated Annotation（注解）](https://www.ossez.com/t/java-deprecated-annotation/13676)
-
-
diff --git a/java/core/core-java-8.md b/java/core/core-java-8.md
new file mode 100644
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--- /dev/null
+++ b/java/core/core-java-8.md
@@ -0,0 +1,14 @@
+## Java 8 核心
+
+本模块中包含有关 Java 8 核心新增功能特性的一些文章。
+
+- [New Features in Java 8](https://www.baeldung.com/java-8-new-features)
+- [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
+- [Java 8 中的设计模式策略](https://www.ossez.com/t/java-8/13978)
+- [Guide to Java 8 Comparator.comparing()](https://www.baeldung.com/java-8-comparator-comparing)
+- [Guide to the Java 8 forEach](https://www.baeldung.com/foreach-java)
+- [Introduction to Spliterator in Java](https://www.baeldung.com/java-spliterator)
+- [Finding Min/Max in an Array with Java](https://www.baeldung.com/java-array-min-max)
+- [Internationalization and Localization in Java 8](https://www.baeldung.com/java-8-localization)
+- [Generalized Target-Type Inference in Java](https://www.baeldung.com/java-generalized-target-type-inference)
+- [[Java 8 核心（第 2 部分） -->]](/core-java-modules/core-java-8-2)
diff --git a/java/core/core-java-strings.md b/java/core/core-java-strings.md
new file mode 100644
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--- /dev/null
+++ b/java/core/core-java-strings.md
@@ -0,0 +1,16 @@
+## Java 字符串（Strings）
+
+本模块中包含有关 Java 字符串（String）有关的文章。
+
+- [Java 使用 char[] Array 还是 String 存储字符串密码](https://www.ossez.com/t/java-char-array-string/14015)
+- [Compact Strings in Java 9](https://www.baeldung.com/java-9-compact-string)
+- [String Not Empty Test Assertions in Java](https://www.baeldung.com/java-assert-string-not-empty)
+- [String Performance Hints](https://www.baeldung.com/java-string-performance)
+- [Java Localization – Formatting Messages](https://www.baeldung.com/java-localization-messages-formatting)
+- [Java – Generate Random String](https://www.baeldung.com/java-random-string)
+- [Java String Interview Questions and Answers](https://www.baeldung.com/java-string-interview-questions)
+- [Java Multi-line String](https://www.baeldung.com/java-multiline-string)
+- [Java 中的 String Pool 简介](https://www.ossez.com/t/java-string-pool/14017)
+- [Fixing “constant string too long” Build Error](https://www.baeldung.com/java-constant-string-too-long-error)
+- [Java 对象如何安全的 toString](https://www.ossez.com/t/java-tostring/14000)
+- [编程常用的几种字符编码](https://www.ossez.com/t/topic/14022)
diff --git a/java/core/index.md b/java/core/index.md
deleted file mode 100644
index a74ed71..0000000
--- a/java/core/index.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# Java 核心编程
-
-[Annotation（注解）](annotation.md ':include')
diff --git a/java/fundamentals/_README.md b/java/fundamentals/_README.md
new file mode 100644
index 0000000..58ed269
--- /dev/null
+++ b/java/fundamentals/_README.md
@@ -0,0 +1,5 @@
+# Java 核心编程
+
+[](concept.md ':include')
+
+[](data-type.md ':include')