JSP求解从传入java、html、sql的成绩。定义一个计算总分数的带参方法，三门课的分数通过参数传递获取。发现代码报错了，该怎么办啊

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>三门的成绩</title>
  </head>
  <body>
  <%
           String java = request.getParameter("java");
        String html = request.getParameter("html");
        String sql = request.getParameter("sql");
        String sum = "";
        sum += Integer.parseInt(java) + Integer.parseInt(html) + Integer.parseInt(sql);
       //报错 public int calc(int java,int html,int sql){
            int sum = java + html + sql;
            return sum;
        }
       %>
       <form id="aa" method="get">
      <p>
          java成绩：<input type="text" name="java" value="<% %>"><br><br>
          html成绩：<input type="text" name="html" value="<% %>"><br><br>
          sql成绩：<input type="text" name="sql" value="<% %>"><br><br>
          <input type="submit" name="sub" value="确定">
      </p>
      总成绩：<input type="text" name="score" value="<%=count%>"><br><br>
       </form>
  </body>
</html>