add const sample

data/1.Java初阶/2.第一个Java程序/1.编辑Java源代码/config.json

 {
   "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
+  "keywords": ["输出", "main", "程序入口"],
   "children": [],
   "export": ["HelloWorld.json"]
 }
\ No newline at end of file

data/1.Java初阶/4.Java的基本语法/1.Java的基本语法格式/config.json

 {
   "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
+  "keywords": ["输出", "循环", "for"],
   "children": [],
   "export": ["app.json"]
 }
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/1.变量的定义/config.json

 {
   "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
+  "keywords": ["变量", "赋值", "定义"],
   "children": [],
-  "export": ["swap.json"]
+  "export": ["vars.json", "swap.json"]
 }
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/1.变量的定义/vars.json

+{
+    "type": "code_options",
+    "author": "刘鑫",
+    "source": "vars.md",
+    "exercise_id":"f990d6473c1c4b0c8947c27681c8f476"
+}
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/1.变量的定义/vars.md

+# 变量定义
+
+以下变量定义哪个是错误的
+
+## 答案
+
+```java
+x = new Int(100)
+```
+
+## 选项
+
+### 常规定义
+
+```java
+String line = "一个字符串变量";
+```
+
+### 变量可以没有初始值
+
+```java
+float x;
+```
+
+### 局部变量在通常情况下可以自动推导类型
+
+```java
+var x = 3.14;
+```

data/1.Java初阶/5.Java中的变量与常量/3.变量的类型转换32目录Java基础入门(第2版)2.2.4变量的作用域/config.json → data/1.Java初阶/5.Java中的变量与常量/3.Java中的常量/config.json

@@ -2,5 +2,5 @@
   "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["solidity.json"]
 }
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/3.Java中的常量/solidity.json

+{
+    "type": "code_options",
+    "author": "刘鑫",
+    "source": "solidity.md",
+    "exercise_id":"45bc14d503364f999f98e5d2faad2fec"
+}
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/3.Java中的常量/solidity.md

+# 常量
+
+下面哪个常量定义是错的？
+
+## 答案
+
+```java
+const int value = 100;
+```
+
+## 选项
+
+### 可以用于局部变量
+
+```java
+final int value = 100;
+```
+
+### 可以用于 public 成员
+
+```java 
+public final int value = 100;
+```
+
+### 可以用于静态成员
+
+```java
+public static final int value = 100;
+
+```
+
+### 可以用于自动类型
+
+```java
+final var x  = 100;
+```
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/4.Java中的常量/config.json

-{
-  "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
-  "children": [],
-  "export": []
-}
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/5.指数记数法/config.json

-{
-  "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
-  "children": [],
-  "export": []
-}
\ No newline at end of file