java.sql.SQLException: No operations allowed after statement closed. at com.mysql.jdbc.Statement.checkClosed(Statement.java:270) at com.mysql.jdbc.Statement.executeQuery(Statement.java:735) at database.MysqlConn.executeQuery(MysqlConn.java:44) at web.product.ProductDetail.doPost(ProductDetail.java:256) at web.product.ProductDetail.doGet(ProductDetail.java:58) at javax.servlet.http.HttpServlet.service(HttpServlet.java:114) at javax.servlet.http.HttpServlet.service(HttpServlet.java:91) at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103) at filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117) at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:73) at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:175) at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:240) at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:263) at com.caucho.server.port.TcpConnection.run(TcpConnection.java:481) at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:685) at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:607) at java.lang.Thread.run(Thread.java:662)