add some simple sources

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

+{
+    "type": "code_options",
+    "author": "刘鑫",
+    "source": "app.md",
+    "exercise_id":"5d4f393434714b0fa3230ac8423db7cc"
+}
\ 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/app.md

+# Java 程序的基本结构
+
+以下选项中，有语法错误的是：
+
+## 缺少必要的语法元素
+
+```java
+public App {
+    public static main(String[] args){
+        for(int i=0; i<10; i++){
+            System.out.println(i);
+        }
+    }
+}
+
+```
+
+## B
+
+```java
+public class App {
+    public static void main(String[] args){
+        for(int i=0; i<10; i++){
+            System.out.println(i);
+        }
+    }
+}
+
+```
+
+## C
+
+```java
+public class App {
+    public static void main(String[] args){
+        for(int i=0; i<10; i++){
+            System.out.println(i);
+        }
+    }
+}
+
+```
+
+## D
+
+```java
+public class App {
+    public static int sum(int[] array){
+        int a = 0;
+        for(int i=0; i<array.length; i++){
+            a += array[i];
+        }
+        return a;
+    }
+}
+```
+
+## E
+
+```java
+public class App {
+    public int sum(int[] array){
+        int a = 0;
+        for(int i=0; i<array.length; i++){
+            a += array[i];
+        }
+        return a;
+    }
+}
+```
+
+## F
+
+```java
+public interface App {
+    default int sum(int[] array){
+        int a = 0;
+        for(int i=0; i<array.length; i++){
+            a += array[i];
+        }
+        return a;
+    }
+}
+```
\ 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

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

data/1.Java初阶/4.Java的基本语法/2.Java中的注释/comment.json

+{
+    "type": "code_options",
+    "author": "刘鑫",
+    "source": "comment.md",
+    "exercise_id":"a666420ebe28430dab8ad4bd99306dfb"
+}
\ No newline at end of file

data/1.Java初阶/4.Java的基本语法/2.Java中的注释/comment.md

+# 注释语法
+
+下面的注释文本中，错误的是：
+
+# 使用了 Python 风格的注释
+
+```java
+package app;
+# a simple class
+
+public class App {
+    public static void main(String[] args){
+        System.out.println("Hello World");
+    }
+}
+```
+
+# 单行注释
+
+```java
+package app;
+// a simple class
+
+public class App {
+    public static void main(String[] args){
+        System.out.println("Hello World");
+    }
+}
+```
+
+# 多行注释
+
+```java
+package app;
+/*
+* Code for comments demo
+* Author: Liu Xin <liuxin@csdn.net>
+* Date: 2021-10-24
+*/
+
+public class App {
+    public static void main(String[] args){
+        System.out.println("Hello World");
+    }
+}
+```
+
+# 代码内的注释
+
+```java
+package app;
+
+public class App {
+    public static void main(String[] args){
+        // print 10 times
+        for(int i; i< 10; i++){
+            System.out.println(i);
+        }
+    }
+}
+```
+
+# 注释混排
+
+```java
+package app;
+
+public class App {
+    public static void main(String[] args){
+        for(int i; i< 10; i++){
+            if(i % 2 == 0) {
+                System.out.println(i*i); // print square value
+            }
+        }
+    }
+}
+```
\ No newline at end of file

data/1.Java初阶/4.Java的基本语法/2.Java中的注释/config.json

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