add hello world

data/1.Java初阶/2.第一个Java程序/1.编辑Java源代码/HelloWord.md

+# Hello World
+
+以下 `Hello World` 程序中，能够正确输出内容的是：
+
+## A
+
+```java
+package app;
+
+public class App {
+    public static void main(String[] args){
+        System.out.println("Hello World");
+    }
+}
+```
+
+## B
+
+```java
+package app;
+
+public class App {
+    public int main(){
+        System.out.printf("Hello World");
+        return 0;
+    }
+}
+```
+
+## C
+
+```java
+package app;
+
+public class App {
+    public static void main(String[] args){
+        println("Hello World");
+    }
+}
+```
+
+## D
+
+```java
+package app;
+import stdout
+
+public class App {
+    public int main(){
+        print("Hello World\n");
+        return 0;
+    }
+}
+
+```
+

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

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

data/1.Java初阶/2.第一个Java程序/config.json

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