나 회원가입 홈페이지 만드는데 DB연동에 자꾸 오류나ㅜㅜ 도와줘ㅜㅜㅜㅜ

DBConnectionPool.java

//package bean.database; 

import java.sql.*; 
import java.util.*;


class DBConnectionPool
{
 private final int maxConnNum=50;
 private Vector connStack=new Vector();
 private String id;
    private String pass;
 private String url;
    private int loanConnNum;

 public DBConnectionPool(String url,String id,String pass){
  this.url=url;
  this.id=id;
  this.pass=pass;
  
 }


 public synchronized Connection getConnection() throws Exception {
  Connection connection=null;

  while(connStack.size()<=0){
                   if(loanConnNum<maxConnNum){ 
           connection=makeConnection();
            break; 
             } 
    else
           wait(); 
      }
           
   if(connection==null){ 
      connection=(Connection)connStack.get(0);
      connStack.removeElementAt(0); 
           if(connection.isClosed()) 
           connection=makeConnection();
           }      
   loanConnNum++; 
   return connection;
  }
     
    private Connection makeConnection() throws Exception{
  Connection connection=DriverManager.getConnection(url,id,pass);
  return connection;
 }
   public synchronized void returnConnection(Connection connection){
    connStack.add(connection);
    loanConnNum--;
    notifyAll();
   }
public synchronized void close() throws Exception{
 for(int i=0;i<connStack.size();i++){
  Connection connection=(Connection)connStack.get(i);
  connection.close();
 }
 connStack.removeAllElements();
}
}

DBConnectionPoolMgr.java

package bean.database;

import bean.database.*;
import java.sql.*;
public class DBConnectionPoolMgr {

 private static DBConnectionPoolMgr instance=null;
        private  DBConnectionPool pool=null;

 private DBConnectionPoolMgr() throws Exception{
      Class.forName("com.mysql.jdbc.Driver");
  
   String url = "jdbc:mysql://localhost/edb";
   String id = "root";
   String pass = "******";
  
   pool=new DBConnectionPool(url,id,pass);
 }

  
 public static synchronized DBConnectionPoolMgr getInstance() throws Exception{
  if(instance==null)
   instance=new DBConnectionPoolMgr();
  return instance;
 }


   public Connection getConnection() throws Exception{
  Connection connection=pool.getConnection();
  return connection;
 }

 public void returnConnection(Connection connection) throws Exception{
              pool.returnConnection(connection);
 }
 public synchronized void close() throws Exception{
  pool.close();
 }
}

Pool파일 클래스만들고 PoolMgr파일 클래스 만들면 private  DBConnectionPool pool=null; 이거 cannot find symbol이래
왜 못찾아 왜 못찾아 왜 못찾는데 ㅜㅜㅜ