import java.sql.*;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;class conn{ String url="jdbc:mysql://127.0.0.1/nariData"; final String user = "nari"; final String pass = "nariacc"; Connection conn = null; Statement st = null; ResultSet rs = null; conn(){  try{   Class.forName("com.mysql.jdbc.Driver");  }catch(Exception e){   e.printStackTrace();  }  try{   System.out.println("in DBManager");   conn = DriverManager.getConnection(url, user, pass);   String sql = "create table test (id int, uid int)";   st = conn.createStatement();   st.execute(sql);  }catch(Exception e){   e.printStackTrace();  } } void insert(){  try{   for(int i=0;i<10;i++){    String sql = "insert into test values("+i+","+i+")";    st.execute(sql);   }  }catch(Exception e){   e.printStackTrace();  } } void query(){  try{   String sql = "select * from test ";   rs = st.executeQuery(sql);   while(rs.next()){    System.out.print("res1: "+rs.getInt(1)+" res2: "+rs.getInt(2)+"/n");   }  }catch(Exception e){   e.printStackTrace();  } } void close(){  try{   rs.close();   st.close();   conn.close();  }catch(Exception e){   e.printStackTrace();  } }}public class mysqltest { public static void main(String[] args) {  // TODO Auto-generated method stub  conn a1 = new conn();  a1.insert();  a1.query();  a1.close(); }}