1. Add build script for Java.

2. Add height limitation for code blocks in extra.css.
3. Fix "节点" to "结点".

docs/chapter_searching/linear_search.md

@@ -15,17 +15,7 @@ comments: true
 === "Java"
 
     ```java title="linear_search.java"
-    /* 线性查找（数组） */
-    int linearSearchArray(int[] nums, int target) {
-        // 遍历数组
-        for (int i = 0; i < nums.length; i++) {
-            // 找到目标元素，返回其索引
-            if (nums[i] == target)
-                return i;
-        }
-        // 未找到目标元素，返回 -1
-        return -1;
-    }
+    [class]{hashing_search}-[func]{linearSearchArray}
     ```
 
 === "C++"
@@ -155,18 +145,7 @@ comments: true
 === "Java"
 
     ```java title="linear_search.java"
-    /* 线性查找（链表） */
-    ListNode linearSearchLinkedList(ListNode head, int target) {
-        // 遍历链表
-        while (head != null) {
-            // 找到目标结点，返回之
-            if (head.val == target)
-                return head;
-            head = head.next;
-        }
-        // 未找到目标结点，返回 null
-        return null;
-    }
+    [class]{hashing_search}-[func]{linearSearchLinkedList}
     ```
 
 === "C++"