Java app on Tomcat return "Network Error (tcp_error)" error

[Khosrow Moossavi]

I've recently deployed a java application to an shared Apache / Tomcat server with MySQL as a backend database.
It's a UNIX server.
Tomcat version is 5.5
It uses mod_jk:

JkMount /* myAJP

The Application is structured with: Struts2 with Spring and Hibernate integration.

Whenever I try to open a page
1) it takes too long (2-3 minutes!) to open a single page (even the most static ones, I mean even the page which is just a Struts Action execute without anything else)

2) The page stops working with following error appear on the browser screen:

Network Error (tcp_error)

A communication error occurred: ""
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to 
requests. You may wish to try again at a later time.

For assistance, contact your network support team. 

The frequency of happening of the second thing is something like 90%!

I could only access catalina.out and there were not anything related to the runtime error or exception. In access.log the response code, almost everytime, was 200 but it wasn't corresponded to the browsing situation.

I even tested the site in Lynx as well, which the same thing was occured there as well.

I've searched about the above error and had not come to any resolution.
I'd really appreciate if anyone could help me find out what's going on!

Regards,
Khosrow.

[Tim Holloway]

My best guess is that you're timing out due to failure of the web application to respond within the allowable interval. Most likely either the application code itself is doing something that takes a long time or it's making a database request that takes a long time to complete.

Just to rule out problems with your pipleline, bypass Apache and access the app directly through Tomcat (or whatever J2Ee server you're using).

[Khosrow Moossavi]

Hello Tim,

Thanks for the reply. The application structure is like this:

applicationContext-hibernate.xml

<beans xmlns="http://www.springframework.org/schema/beans"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xmlns:aop="http://www.springframework.org/schema/aop"
		xmlns:tx="http://www.springframework.org/schema/tx"
		xsi:schemaLocation="
			http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
			http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
			http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

	

	<!-- ========================= RESOURCE DEFINITIONS ========================= -->
  
	<!-- Configurer that replaces ${...} placeholders with values from a properties file -->
	<!-- (in this case, JDBC-related settings for the dataSource definition below) -->
	<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="location"><value>/WEB-INF/jdbc.properties</value></property>
	</bean>

	<!-- Local DataSource that works in any environment -->
	<!-- Note that DriverManagerDataSource does not pool; it is not intended for production -->
	
	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName"><value>${jdbc.driverClassName}</value></property>
		<property name="url"><value>${jdbc.url}</value></property>
		<property name="username"><value>${jdbc.username}</value></property>
		<property name="password"><value>${jdbc.password}</value></property>
	</bean>
	

	<!-- JNDI DataSource for J2EE environments -->

	<!-- Hibernate SessionFactory -->
	<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
		<property name="dataSource"><ref local="dataSource"/></property>
		
		<property name="configLocation">
			<value>classpath:my\classpath\domain\hibernate.cfg.xml</value>
		</property>

		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">${hibernate.dialect}</prop>
				<prop key="hibernate.show_sql">true</prop>
			</props>
		</property>
	</bean>


	<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
	<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
		<property name="sessionFactory"><ref local="sessionFactory"/></property>
	</bean>


	<import resource="/spring-context/spring-hibernate-daos.xml"/>
	<import resource="/spring-context/spring-hibernate-services.xml"/>
	<import resource="/spring-context/spring-hibernate-actions.xml"/>
</beans>

spring-hibernate-actions.xml

        ......
	<bean id="FirstAction" class="my.com.package.struts.action.FirstAction">
		<property name="firstService"><ref bean="firstService"/></property>
	</bean>  
	
	<bean id="SecondAction" class="my.com.package.struts.action.SecondAction">
		<property name="secondService"><ref bean="secondService"/></property>
	</bean>
        ......

spring-hibernate-services.xml

        ......
	<bean id="firstService" class="my.com.package.service.FirstServiceImpl">
		<property name="firstDAO"><ref bean="firstDAO"/></property>
	</bean>
	<bean id="secondService" class="my.com.package.service.SecondServiceImpl">
		<property name="secondDAO"><ref bean="secondDAO"/></property>
	</bean>
        ......

spring-hibernate-daos.xml

        ......
	<bean id="firstDAO" class="my.com.package.dao.FirstDAOImpl">
		<property name="sessionFactory"><ref bean="sessionFactory"/></property>
	</bean>
	<bean id="secondDAO" class="my.com.package.dao.SecondDAOImpl">
		<property name="sessionFactory"><ref bean="sessionFactory"/></property>
	</bean>
        ......

FirstDAOImpl.java

package my.com.package.dao;

import java.util.List;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import my.com.package.domain.First;


public class FirstDAOImpl extends HibernateDaoSupport implements FirstDAO {
	/**
	 * DAO Constructor
	 */
	public AboutUsDAOImpl() {}
	
	
	@SuppressWarnings("unchecked")
	@Override
	public List<First> getContent(String lang) {
		List<First> firstContent = this.getHibernateTemplate().find("from First where  isDeleted=0");
		
		return firstContent ;
	}
}

Is this a correct way? or even an accurate one? Should I close something that I'm not aware of right now?
And by the way, what did you mean by "bypass Apache and access the app directly through Tomcat ". How can I do that?

Regards,
Khosrow.