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'Too many connections' error after redeploying webapp

I am using AbstractRoutingDataSource to create multitenancy in my application. I noticed that after a few redeployments of the webapp from my IDE I eventually get the MySQL error "Too many connections".
After further investigations, I found out that when I run the MySQL command show processlist;, I see that the open connection amount is increased by 10 after each deployment, which probably means that the connection pool is somehow still alive somewhere.
Before I used AbstractRoutingDataSource I used the default spring datasource configuration (using application.properties) and it worked fine.
Here's the Multitenant configuration class:
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.util.*;
import java.util.stream.Collectors;
/**
* Created by Alon Segal on 16/03/2017.
*/
#Configuration
public class MultitenantConfiguration {
#Autowired
private DataSourceProperties properties;
/**
* Defines the data source for the application
*
* #return
*/
#Bean
#ConfigurationProperties(
prefix = "spring.datasource"
)
public DataSource dataSource() {
//Creating datasources map "resolvedDataSources" here
MultitenantDataSource dataSource = new MultitenantDataSource();
dataSource.setDefaultTargetDataSource(defaultDataSource());
dataSource.setTargetDataSources(resolvedDataSources);
// Call this to finalize the initialization of the data source.
dataSource.afterPropertiesSet();
return dataSource;
}
/**
* Creates the default data source for the application
*
* #return
*/
private DataSource defaultDataSource() {
.
.
.
}
}
And the datasource class:
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
* Created by Alon Segal on 16/03/2017.
*/
public class MultitenantDataSource extends AbstractRoutingDataSource {
#Override
protected Object determineCurrentLookupKey() {
return TenantContext.getCurrentTenant();
}
}
I also tried to use #Bean(destroyMethod = "close") but there is not close method defined on AbstractRoutingDataSource.
I searched everywhere but could not find and answer. Can someone help me understand what's preventing the connection pool from being released between redeployments?
Thanks in advance.

Ok so I eventually solved the issue by giving up on using Spring's AbstractRoutingDataSource and instead using Hibernate's mechanism for multitenancy based on the solution that can be found in this article.
Long story short
You need to do 3 steps:
Step 1: Create a CurrentTenantIdentifierResolver
#Component
public class TenantIdentifierResolver implements CurrentTenantIdentifierResolver {
#Override
public String resolveCurrentTenantIdentifier() {
String tenantId = TenantContext.getCurrentTenant();
if (tenantId != null) {
return tenantId;
}
return DEFAULT_TENANT_ID;
}
#Override
public boolean validateExistingCurrentSessions() {
return true;
}
}
Step 2: Create a MultiTenantConnectionProvider
#Component
public class MultiTenantConnectionProviderImpl implements MultiTenantConnectionProvider {
#Autowired
private DataSource dataSource;
#Override
public Connection getAnyConnection() throws SQLException {
return dataSource.getConnection();
}
#Override
public void releaseAnyConnection(Connection connection) throws SQLException {
connection.close();
}
#Override
public Connection getConnection(String tenantIdentifie) throws SQLException {
String tenantIdentifier = TenantContext.getCurrentTenant();
final Connection connection = getAnyConnection();
try {
if (tenantIdentifier != null) {
connection.createStatement().execute("USE " + tenantIdentifier);
} else {
connection.createStatement().execute("USE " + DEFAULT_TENANT_ID);
}
}
catch ( SQLException e ) {
throw new HibernateException(
"Could not alter JDBC connection to specified schema [" + tenantIdentifier + "]",
e
);
}
return connection;
}
#Override
public void releaseConnection(String tenantIdentifier, Connection connection) throws SQLException {
try {
connection.createStatement().execute( "USE " + DEFAULT_TENANT_ID );
}
catch ( SQLException e ) {
throw new HibernateException(
"Could not alter JDBC connection to specified schema [" + tenantIdentifier + "]",
e
);
}
connection.close();
}
#SuppressWarnings("rawtypes")
#Override
public boolean isUnwrappableAs(Class unwrapType) {
return false;
}
#Override
public <T> T unwrap(Class<T> unwrapType) {
return null;
}
#Override
public boolean supportsAggressiveRelease() {
return true;
}
}
Step 3: Wire it up
#Configuration
public class HibernateConfig {
#Autowired
private JpaProperties jpaProperties;
#Bean
public JpaVendorAdapter jpaVendorAdapter() {
return new HibernateJpaVendorAdapter();
}
#Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource,
MultiTenantConnectionProvider multiTenantConnectionProviderImpl,
CurrentTenantIdentifierResolver currentTenantIdentifierResolverImpl) {
Map<String, Object> properties = new HashMap<>();
properties.putAll(jpaProperties.getHibernateProperties(dataSource));
properties.put(Environment.MULTI_TENANT, MultiTenancyStrategy.SCHEMA);
properties.put(Environment.MULTI_TENANT_CONNECTION_PROVIDER, multiTenantConnectionProviderImpl);
properties.put(Environment.MULTI_TENANT_IDENTIFIER_RESOLVER, currentTenantIdentifierResolverImpl);
LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
em.setDataSource(dataSource);
em.setPackagesToScan("com.autorni");
em.setJpaVendorAdapter(jpaVendorAdapter());
em.setJpaPropertyMap(properties);
return em;
}
}

Websockets Tomcat 7 does not work in existing project

I try to run a websocket server in a Java project that was running on Tomcat6. I have set up a Tomcat 7 server where the project now is running on.
First I tried to run the socket example of Tomcat7. This run perfectly. I copied this class to my old project. When I run the old project again all the functionalities are working like before but only the websocket server doe not work.
This is the ChatAnnotation class that I have copied from the examples from Tomcat to my old project.
import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicInteger;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import org.apache.log4j.Logger;
#ServerEndpoint(value = "/websocket/chat")
public class ChatAnnotation {
private static Logger logger = Logger.getLogger(ChatAnnotation.class);
private static final String GUEST_PREFIX = "Guest";
private static final AtomicInteger connectionIds = new AtomicInteger(0);
private static final Set<ChatAnnotation> connections = new CopyOnWriteArraySet<ChatAnnotation>();
private final String nickname;
private Session session;
public ChatAnnotation() {
nickname = GUEST_PREFIX + connectionIds.getAndIncrement();
logger.info("ws instance");
}
#OnOpen
public void start(Session session) {
this.session = session;
connections.add(this);
String message = String.format("* %s %s", nickname, "has joined.");
broadcast(message);
}
#OnClose
public void end() {
connections.remove(this);
String message = String.format("* %s %s", nickname, "has disconnected.");
broadcast(message);
}
#OnMessage
public void incoming(String message) {
// Never trust the client
String filteredMessage = String.format("%s: %s", nickname, message.toString());
broadcast(filteredMessage);
}
#OnError
public void onError(Throwable t) throws Throwable {
logger.error("Chat Error: " + t.toString(), t);
}
private static void broadcast(String msg) {
for (ChatAnnotation client : connections) {
try {
synchronized (client) {
client.session.getBasicRemote().sendText(msg);
}
} catch (IOException e) {
logger.debug("Chat Error: Failed to send message to client", e);
connections.remove(client);
try {
client.session.close();
} catch (IOException e1) {
// Ignore
}
String message = String.format("* %s %s", client.nickname, "has been disconnected.");
broadcast(message);
}
}
}
}
I have noting added in my web.xml. In my old project are also tcpsockets used can this be the problem?
Can anyone help me with this problem?
EDIT
Class added:
import java.util.HashSet;
import java.util.Set;
import javax.websocket.Endpoint;
import javax.websocket.server.ServerApplicationConfig;
import javax.websocket.server.ServerEndpointConfig;
import org.apache.log4j.Logger;
public class ExamplesConfig implements ServerApplicationConfig {
private static Logger log = Logger.getLogger(ChatAnnotation.class);
public Set<ServerEndpointConfig> getEndpointConfigs(Set<Class<? extends Endpoint>> endpointClasses) {
Set<ServerEndpointConfig> result = new HashSet<ServerEndpointConfig>();
log.info("getEndpointConfigs");
return result;
}
public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
log.info("getAnnotatedEndpointClasses");
return scanned;
}
}

Java websocket server use return value of ServerApplicationConfig interface to deploy programmatic endpoints and for annotated endpoints.
For Tomcat example, if you change the package name of ChatAnnotation. You have to modify websocket.ExamplesConfig too.
public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
// Deploy all WebSocket endpoints defined by annotations in the examples
// web application. Filter out all others to avoid issues when running
// tests on Gump
Set<Class<?>> results = new HashSet<>();
for (Class<?> clazz : scanned) {
String name = clazz.getPackage().getName();
boolean ok = name.startsWith("websocket.");
if (ok) {
results.add(clazz);
}
}
return scanned;
}
The getAnnotatedEndpointClasses(scanned) only return classes which package name start with websocket. Unmatched classes will not deployed even they have #ServerEndpoint declarations.

How to call a #Remote EJB in another client project

I need to be able to call a save() method from this simple swing java app to my web app that is published on the server with the beans I use to save a new Entity type class Persona, that has name, address, email.
Im using wildfly 8.x for my server and have my web app published like this:
23:51:10,641 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-3) JNDI bindings for session bean named ContactoDAO in deployment unit deployment "proyectobase.war" are as follows:
java:global/proyectobase/ContactoDAO!edu.ups.appdis.proyectobase.negocio.ContactoDAO
java:app/proyectobase/ContactoDAO!edu.ups.appdis.proyectobase.negocio.ContactoDAO
java:module/ContactoDAO!edu.ups.appdis.proyectobase.negocio.ContactoDAO
java:global/proyectobase/ContactoDAO
java:app/proyectobase/ContactoDAO
java:module/ContactoDAO
This is my ContactoDAO Bean:
package edu.ups.appdis.proyectobase.negocio;
import java.io.Serializable;
import java.util.List;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.Query;
import edu.ups.appdis.proyectobase.modelo.Persona;
#Stateless
// #Remote(Serializable.class)
#Remote
public class ContactoDAO implements Serializable {
// #Inject
// private Logger log;
/**
*
*/
#Inject
private EntityManager em;
public void save(Persona persona) {
// if (em.find(Persona.class, persona.getCodiog()) == null) {
insertar(persona);
// } else {
//
// update(persona);
// }
}
public void test() {
System.out.println("si funciona ");
}
public void insertar(Persona persona) {
em.persist(persona);
}
public void update(Persona persona) {
em.merge(persona);
}
public void remove(int codigo) {
Persona persona = em.find(Persona.class, codigo);
em.remove(persona);
}
public Persona read(int codigo) {
System.out.println("insertado objeto persona");
return em.find(Persona.class, codigo);
}
public List<Persona> getContactos() {
String sql = "SELECT p FROM Persona p";
Query query = em.createQuery(sql, Persona.class);
List<Persona> personas = query.getResultList();
return personas;
}
}
On my simple client swing app I have it set up like this:
package cliente.gui;
import java.awt.EventQueue;
............
import javax.ejb.EJB;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import java.security.Security;
import java.util.Hashtable;
import edu.ups.appdis.proyectobase.modelo.Persona;
import edu.ups.appdis.proyectobase.negocio.*;
public class guiPersona {
// #EJB(lookup = "java:global/proyectobase/ContactoDAO!edu.ups.appdis.proyectobase.negocio.ContactoDAO")
#EJB(lookup = "java:global/proyectobase/ContactoDAO")
ContactoDAO contactoDAO;
private JFrame frame;
private JTextField textNombre;
private JTextField textDireccion;
private JTextField textEmail;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
guiPersona window = new guiPersona();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*
* #throws NamingException
*/
public guiPersona() {
initialize();
}
...........
JButton btnGuardar = new JButton("Guardar");
btnGuardar.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
contactoDAO.test();
if (textDireccion.getText() != "" && textEmail.getText() != "" && textNombre.getText() != "") {
Persona p = new Persona();
p.setNombre(textNombre.getText());
p.setDireccion(textDireccion.getText());
p.setEmail(textEmail.getText());
contactoDAO.save(p);
textNombre.setText("");
textDireccion.setText("");
textEmail.setText("");
}
}
});
You can see in the code above I use this to call my bean in the other proyect:
#EJB(lookup = "java:global/proyectobase/ContactoDAO")
ContactoDAO contactoDAO;
And on my button to save the new entry I use this:
if (textDireccion.getText() != "" && textEmail.getText() != "" && textNombre.getText() != "") {
Persona p = new Persona();
p.setNombre(textNombre.getText());
p.setDireccion(textDireccion.getText());
p.setEmail(textEmail.getText());
contactoDAO.save(p);
textNombre.setText("");
textDireccion.setText("");
textEmail.setText("");
}
}
});
I also tried using this:
#EJB(lookup="java:global/proyectobase/ContactoDAO!edu.ups.appdis.proyectobase.negocio.ContactoDAO")
ContactoDAO contactoDAO;
I keep getting a null pointer exception on my ContactoDAO but is it maybe because the lookup is not finding anything or Im not using it right, I dont really know. My question is what would be another way of calling my save method from my bean in another simple swing project, or maybe Im missing something else whenever I use the #EJB?
EDIT:
This is my beans.xml in case you were wondering.
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd" bean-discovery-mode="all">
</beans>

From the log it seems that your ContactDAO and all its dependencies are correct getting initialized on the server. On the standalone swing client possibly you are missing jboss-ejb-client.properties in your META-INF folder or you can also explicitly set the initial context properties and do the JNDI lookup manually.
SE POST
Also you should make sure to include the jboss-client.jar file in the classpath of swing client project.
Wildfly Developer Guide
If you get a Authentication failed exception then you need to add username/password properties to the InitialContext and run the add-user.sh script on the server
Add User

JNDI Initial Context & Lookup_problem for EJB 3

This issue is very common. I have read some articles but can't find the problem. I want to create a simple HelloWorld program in EJB 3.0, eclipse luna, jboss 7.1.1 Final.
Here is my bean:
package com.tcs.HelloWorldPack;
import javax.ejb.Stateless;
/**
* Session Bean implementation class HelloWorld
*/
#Stateless(mappedName="HelloWorldBean")
public class HelloWorld implements HelloWorldRemote {
/**
* Default constructor.
*/
public HelloWorld() {
// TODO Auto-generated constructor stub
}
#Override
public void displayMsg() {
// TODO Auto-generated method stub
System.out.println("Hello World!!");
}
}
Here is my remote interface:
package com.tcs.HelloWorldPack;
import javax.ejb.Local;
//import javax.ejb.Remote;
import javax.ejb.Remote;
#Remote
public interface HelloWorldRemote {
void displayMsg();
}
Here is my client which is running in the same machine:
package com.tcs.HelloWorldClient;
import java.util.Hashtable;
import java.util.Properties;
import com.tcs.HelloWorldPack.*;
import javax.ejb.EJB;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class HelloWorldClient {
public static void main(String[] args) throws NamingException {
final Hashtable jndiProperties = new Hashtable();
jndiProperties.put(Context.URL_PKG_PREFIXES, "org.jboss.ejb.client.naming");
jndiProperties.put(javax.naming.Context.SECURITY_PRINCIPAL, "myUser");
jndiProperties.put(javax.naming.Context.SECURITY_CREDENTIALS, "myPass");
// jndiProperties.put(javax.naming.Context.PROVIDER_URL, "jnp://localhost:1099");
// jndiProperties.put(javax.naming.Context.INITIAL_CONTEXT_FACTORY, "org.jboss.naming.remote.client.InitialContextFactory");
jndiProperties.put("jboss.naming.client.ejb.context", true);
final Context context = new InitialContext(jndiProperties);
final String appName= "HeloWorldEJBEAR";
final String moduleName= "";
final String distinctName ="";
final String beanName = "HeloWorld";
final String viewClassName = "com.tcs.HelloWorldPack.HelloWorldRemote";
HelloWorldRemote hello = (HelloWorldRemote) context.lookup("ejb:" + appName + "/" + moduleName + "/" + distinctName + "/" + beanName + "!" + viewClassName);
hello.displayMsg();
}
}
This is my jboss-ejb-client.properties file:
remote.connectionprovider.create.options.org.xnio.Options.SSL_ENABLED=false
remote.connections=default
remote.connection.default.host=localhost
remote.connection.default.port = 4447
remote.connection.default.connect.options.org.xnio.Options.SASL_POLICY_NOANONYMOUS=false
remote.connection.default.username=myUser
remote.connection.default.password=myPass
I have put the properties file in the classpath also.But this is happening when I am trying to run it:
Exception in thread "main" java.lang.IllegalStateException: No EJB receiver available for handling [appName:HeloWorldEJBEAR,modulename:,distinctname:] combination for invocation context org.jboss.ejb.client.EJBClientInvocationContext#413ded77
at org.jboss.ejb.client.EJBClientContext.requireEJBReceiver(EJBClientContext.java:584)
at org.jboss.ejb.client.ReceiverInterceptor.handleInvocation(ReceiverInterceptor.java:119)
at org.jboss.ejb.client.EJBClientInvocationContext.sendRequest(EJBClientInvocationContext.java:181)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:136)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:121)
at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:104)
at com.sun.proxy.$Proxy0.displayMsg(Unknown Source)
at com.tcs.HelloWorldClient.HelloWorldClient.main(HelloWorldClient.java:71)
Jan 08, 2015 3:34:44 PM org.jboss.ejb.client.remoting.ChannelAssociation$ResponseReceiver handleEnd
INFO: Channel Channel ID de8d2aa6 (outbound) of Remoting connection 44477156 to localhost/127.0.0.1:4447 can no longer process messages
I have also uploaded my directory structure. I am new to the EJB concept. Please help me to find where is the problem. Thanks in advance.

Your module name is an empty String, but the module name can't be an empty string in the JNDI name.
Look here
you have to set the name of your ejb module .jar, without the .jar suffix.
final String moduleName = "HeloWorldEJB";
Then it should work.

As you are out to do a simple example lets keeep it simple [KISS],Most of your code is correct the catch is the client, I have simplified the client code, added my comments in client hope its self explanatory.And.... Added on EJB #javax.ejb.Stateless(name = "HelloWorldEJB") //This is portable No Vendor locked in. Alternative is mappedName [removed from your code #Stateless(mappedName="HelloWorldBean") p]which i believe is more weblogic and glassfish centric.
Ensure you have client.jar in your class path. this is the only jar you will have to add aftr you have created the EJB project in intelija or eclipse or any other ide.
I have deployed the EJB's in glassfish container once ear deployed successfully, run the client.
Apart from the below code you wont need any other configurations. This code is portable and should work on most containers however Surprises is fun do run as is and let me know .....
Once the below works for you you can add other jndi properties as per your project requirement and move on.....
==============================
The Remote
package com.au.ejbs;
import javax.ejb.Remote;
#Remote
public interface HelloWorldI {
String displayMessage(String message);
}
=================================
2. The Impl
package com.au.ejbs;
import javax.ejb.Remote;
#javax.ejb.Stateless(name = "HelloWorldEJB")
public class HelloWorld implements HelloWorldI {
#Override
public String displayMessage(String message) {
// TODO Auto-generated method stub
return "Returning from Remote" + message;
}
}
======================================
3. The client
package com.au.clients;
import com.au.ejbs.HelloWorldI;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class HelloWorldT {
public static void main(String[] args) throws NamingException {
Context context = new InitialContext();
HelloWorldI helloWorldI = (HelloWorldI)context.lookup("java:global/ejb3_2_ear_exploded/ejb/HelloWorldEJB");
//portable syntax java:global/[ ear name]/[module name normally the jar name in my case ejb.jar within the ear, ejb3_2_ear_exploded]/name in ....javax.ejb.Stateless(name = "HelloWorldEJB")/
System.out.println( "output " + helloWorldI.displayMessage("From Client with luv...."));
}
}
===================
4. output
output Returning from RemoteFrom Client with luv....

Grizzly Http Server - accepting only one connection at a time

I have a Grizzly Http Server with Async processing added. It is queuing my requests and processing only one request at a time, despite adding async support to it.
Path HttpHandler was bound to is: "/"
Port number: 7777
Behavior observed when I hit http://localhost:7777 from two browsers simultaneously is:
Second call waits till first one is completed. I want my second http call also to work simultaneously in tandom with first http call.
EDIT Github link of my project
Here are the classes
GrizzlyMain.java
package com.grizzly;
import java.io.IOException;
import java.net.URI;
import javax.ws.rs.core.UriBuilder;
import org.glassfish.grizzly.http.server.HttpServer;
import org.glassfish.grizzly.http.server.NetworkListener;
import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
import org.glassfish.grizzly.strategies.WorkerThreadIOStrategy;
import org.glassfish.grizzly.threadpool.ThreadPoolConfig;
import com.grizzly.http.IHttpHandler;
import com.grizzly.http.IHttpServerFactory;
public class GrizzlyMain {
private static HttpServer httpServer;
private static void startHttpServer(int port) throws IOException {
URI uri = getBaseURI(port);
httpServer = IHttpServerFactory.createHttpServer(uri,
new IHttpHandler(null));
TCPNIOTransport transport = getListener(httpServer).getTransport();
ThreadPoolConfig config = ThreadPoolConfig.defaultConfig()
.setPoolName("worker-thread-").setCorePoolSize(6).setMaxPoolSize(6)
.setQueueLimit(-1)/* same as default */;
transport.configureBlocking(false);
transport.setSelectorRunnersCount(3);
transport.setWorkerThreadPoolConfig(config);
transport.setIOStrategy(WorkerThreadIOStrategy.getInstance());
transport.setTcpNoDelay(true);
System.out.println("Blocking Transport(T/F): " + transport.isBlocking());
System.out.println("Num SelectorRunners: "
+ transport.getSelectorRunnersCount());
System.out.println("Num WorkerThreads: "
+ transport.getWorkerThreadPoolConfig().getCorePoolSize());
httpServer.start();
System.out.println("Server Started #" + uri.toString());
}
public static void main(String[] args) throws InterruptedException,
IOException, InstantiationException, IllegalAccessException,
ClassNotFoundException {
startHttpServer(7777);
System.out.println("Press any key to stop the server...");
System.in.read();
}
private static NetworkListener getListener(HttpServer httpServer) {
return httpServer.getListeners().iterator().next();
}
private static URI getBaseURI(int port) {
return UriBuilder.fromUri("https://0.0.0.0/").port(port).build();
}
}
HttpHandler (with async support built in)
package com.grizzly.http;
import java.io.IOException;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import javax.ws.rs.core.Application;
import org.glassfish.grizzly.http.server.HttpHandler;
import org.glassfish.grizzly.http.server.Request;
import org.glassfish.grizzly.http.server.Response;
import org.glassfish.grizzly.http.util.HttpStatus;
import org.glassfish.grizzly.threadpool.GrizzlyExecutorService;
import org.glassfish.grizzly.threadpool.ThreadPoolConfig;
import org.glassfish.jersey.server.ApplicationHandler;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.server.spi.Container;
import com.grizzly.Utils;
/**
* Jersey {#code Container} implementation based on Grizzly
* {#link org.glassfish.grizzly.http.server.HttpHandler}.
*
* #author Jakub Podlesak (jakub.podlesak at oracle.com)
* #author Libor Kramolis (libor.kramolis at oracle.com)
* #author Marek Potociar (marek.potociar at oracle.com)
*/
public final class IHttpHandler extends HttpHandler implements Container {
private static int reqNum = 0;
final ExecutorService executorService = GrizzlyExecutorService
.createInstance(ThreadPoolConfig.defaultConfig().copy()
.setCorePoolSize(4).setMaxPoolSize(4));
private volatile ApplicationHandler appHandler;
/**
* Create a new Grizzly HTTP container.
*
* #param application
* JAX-RS / Jersey application to be deployed on Grizzly HTTP
* container.
*/
public IHttpHandler(final Application application) {
}
#Override
public void start() {
super.start();
}
#Override
public void service(final Request request, final Response response) {
System.out.println("\nREQ_ID: " + reqNum++);
System.out.println("THREAD_ID: " + Utils.getThreadName());
response.suspend();
// Instruct Grizzly to not flush response, once we exit service(...) method
executorService.execute(new Runnable() {
#Override
public void run() {
try {
System.out.println("Executor Service Current THREAD_ID: "
+ Utils.getThreadName());
Thread.sleep(25 * 1000);
} catch (Exception e) {
response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR_500);
} finally {
String content = updateResponse(response);
System.out.println("Response resumed > " + content);
response.resume();
}
}
});
}
#Override
public ApplicationHandler getApplicationHandler() {
return appHandler;
}
#Override
public void destroy() {
super.destroy();
appHandler = null;
}
// Auto-generated stuff
#Override
public ResourceConfig getConfiguration() {
return null;
}
#Override
public void reload() {
}
#Override
public void reload(ResourceConfig configuration) {
}
private String updateResponse(final Response response) {
String data = null;
try {
data = new Date().toLocaleString();
response.getWriter().write(data);
} catch (IOException e) {
data = "Unknown error from our server";
response.setStatus(500, data);
}
return data;
}
}
IHttpServerFactory.java
package com.grizzly.http;
import java.net.URI;
import org.glassfish.grizzly.http.server.HttpServer;
import org.glassfish.grizzly.http.server.NetworkListener;
import org.glassfish.grizzly.http.server.ServerConfiguration;
/**
* #author smc
*/
public class IHttpServerFactory {
private static final int DEFAULT_HTTP_PORT = 80;
public static HttpServer createHttpServer(URI uri, IHttpHandler handler) {
final String host = uri.getHost() == null ? NetworkListener.DEFAULT_NETWORK_HOST
: uri.getHost();
final int port = uri.getPort() == -1 ? DEFAULT_HTTP_PORT : uri.getPort();
final NetworkListener listener = new NetworkListener("IGrizzly", host, port);
listener.setSecure(false);
final HttpServer server = new HttpServer();
server.addListener(listener);
final ServerConfiguration config = server.getServerConfiguration();
if (handler != null) {
config.addHttpHandler(handler, uri.getPath());
}
config.setPassTraceRequest(true);
return server;
}
}

It seems the problem is the browser waiting for the first request to complete, and thus more a client-side than a server-side issue. It disappears if you test with two different browser processes, or even if you open two distinct paths (let's say localhost:7777/foo and localhost:7777/bar) in the same browser process (note: the query string partecipates in making up the path in the HTTP request line).
How I understood it
Connections in HTTP/1.1 are persistent by default, ie browsers recycle the same TCP connection over and over again to speed things up. However, this doesn't mean that all requests to the same domain will be serialized: in fact, a connection pool is allocated on a per-hostname basis (source). Unfortunately, requests with the same path are effectively enqueued (at least on Firefox and Chrome) - I guess it's a device that browsers employ to protect server resources (and thus user experience)
Real-word applications don't suffer from this because different resources are deployed to different URLs.
DISCLAIMER: I wrote this answer based on my observations and some educated guess. I think things may actually be like this, however a tool like Wireshark should be used to follow the TCP stream and definitely assert this is what happens.