Cannot call senderror() after response has been committed Tomcat Spring MVC - spring

Question

If I am returning a Employee object in my controller class, I get a response from my REST service. But if I am trying to return a List, then I frequently get this error:
Error:cannot call senderror() after the response has been committed
(Also atttached the image)
I am using Eclipse, tomcat, maven and making a spring REST service.
Here is my Controller class code snippetwhich is returning Employee, and everything is fine and I can see my JSON data on browser. But when I change Employee to List as my new return type, I receive the following error and my Eclipse also hangs for few minutes. I think my problem could have to do with the JSON convertor. Please help.
#Controller
#RequestMapping("/emp")
public class EMPController {
#Autowired
EmployeeService empservice;
#RequestMapping("byname3/{name}")
#ResponseBody
public Employee getByName(#PathVariable String name) {
System.out.println("Inside getByName()..successfully..EMPController");
.....
......
My dispatcher-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
<context:component-scan base-package="com.spice.controller" />
<context:component-scan base-package="com.spice.daoImpl" />
<context:component-scan base-package="com.spice.serviceImpl " />
<mvc:annotation-driven /> <!-- tHIS HELPS IN AUTOMATIC JSON-TO-JAVA AND VICE VERSA CONVERTUION -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"></property>
<property name="url" value="jdbc:oracle:thin:#localhost:1521:xe"></property>
<property name="username" value="tiwari"></property>
<property name="password" value="tiwari"></property>
</bean>
<bean id="mysessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<!-- eARLIER i WAS USING org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean -->
<!-- BUT THIS LEADS TO SOME CACHE PROVIDER CLASS NOT FOUND EXCEPTION -->
<!-- ALSO THIS AnnotationSessionFactoryBean IS NOW REPLACED BY LocalSessionFactoryBean -->
<property name="dataSource" ref="dataSource"></property>
<property name="annotatedClasses">
<list>
<value>com.spice.beans.Employee</value>
<value>com.spice.beans.Address</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.OracleDialect</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager"
class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<!-- THIS CLASS IS COMPATIBLE WITH ABOVE VERSIONS OF SPRING AND HIBERNATE -->
<property name="sessionFactory" ref="mysessionFactory" />
</bean>
</beans>

Answer 1

Error:cannot call senderror() after the response has been committed
(Also atttached the image)
This error is an aftermath of a different error. The server encountered a main exception with your application and hence it tried to call HttpServletResponse#sendError(), which throws IllegalStateException in turn.