ybiquitous/EchoEndPoint.java

## README
# Project Directory Tree #
/
├── pom.xml
└── src
    └── main
        ├── java
        │   └── jsr356
        │       └── example
        │           └── EchoEndPoint.java
        └── webapp
            └── index.html

# Start Server #
Run command 'mvn jetty:run'

## EchoEndPoint.java
package jsr356.example;

import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.logging.Logger;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint(value = "/echo")
public class EchoEndPoint {

    private static final Logger log = Logger.getLogger(EchoEndPoint.class.getName());

    private static final Set<Session> sessions = new CopyOnWriteArraySet<>();

    @OnOpen
    public void onOpen(Session session) {
        log.info("{" + session.getId() +  "} connected");
        sessions.add(session);
    }

    @OnClose
    public void onClose(Session session) {
        log.info("{" + session.getId() +  "} closed");
        sessions.remove(session);
    }

    @OnMessage
    public void echo(String message) throws IOException {
        for (Session session : sessions) {
            if (session.isOpen()) {
                log.info("{" + session.getId() + "} echo '" + message + "'");
                session.getBasicRemote().sendText(message);
            }
        }
    }

}

## index.html
<!DOCTYPE html>
<html>
  <head>
    <title>Echo</title>
  </head>
  <body>
    <input id="msg" type="text" />
    <button id="echo">Echo</button>
    <button id="close">Close</button>
    <ul id="area"></ul>
    <script>
     var area = document.getElementById("area");
     var msg = document.getElementById("msg");
     var ws = new WebSocket("ws://localhost:8080/echo");
     ws.onopen = function(event) {
       console.log(event);
     };
     ws.onclose = function(event) {
       console.log(event);
     };
     ws.onmessage = function(event) {
       console.log(event);
       var entry = document.createElement("li");
       entry.textContent = event.data;
       area.appendChild(entry);
     }
     ws.onerror = function(event) {
       console.log(event);
     }
     document.getElementById("echo").onclick = function() {
       ws.send(msg.value);
     };
     document.getElementById("close").onclick = function() {
       ws.close();
     };
    </script>
  </body>
</html>

## pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>jsr356-example</groupId>
  <artifactId>jsr356-example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <properties>
    <encoding>UTF-8</encoding>
    <javaVersion>1.7</javaVersion>
    <jettyVersion>9.1.0.v20131115</jettyVersion><!-- 9.1.0+ -->
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </properties>
  <dependencies>
    <dependency>
      <groupId>javax.websocket</groupId>
      <artifactId>javax.websocket-api</artifactId>
      <version>1.0</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>${javaVersion}</source>
          <target>${javaVersion}</target>
          <compilerVersion>${javaVersion}</compilerVersion>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-maven-plugin</artifactId>
        <version>${jettyVersion}</version>
        <configuration>
          <reload>manual</reload>
          <systemProperties>
            <systemProperty>
              <name>java.util.logging.SimpleFormatter.format</name>
              <value>%1$tF %1$tT,%1$tL %4$s - %5$s%6$s%n</value>
            </systemProperty>
          </systemProperties>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>
	# Project Directory Tree #
	/
	├── pom.xml
	└── src
	└── main
	├── java
	│ └── jsr356
	│ └── example
	│ └── EchoEndPoint.java
	└── webapp
	└── index.html

	# Start Server #
	Run command 'mvn jetty:run'
	package jsr356.example;

	import java.io.IOException;
	import java.util.Set;
	import java.util.concurrent.CopyOnWriteArraySet;
	import java.util.logging.Logger;

	import javax.websocket.OnClose;
	import javax.websocket.OnMessage;
	import javax.websocket.OnOpen;
	import javax.websocket.Session;
	import javax.websocket.server.ServerEndpoint;

	@ServerEndpoint(value = "/echo")
	public class EchoEndPoint {

	private static final Logger log = Logger.getLogger(EchoEndPoint.class.getName());

	private static final Set<Session> sessions = new CopyOnWriteArraySet<>();

	@OnOpen
	public void onOpen(Session session) {
	log.info("{" + session.getId() + "} connected");
	sessions.add(session);
	}

	@OnClose
	public void onClose(Session session) {
	log.info("{" + session.getId() + "} closed");
	sessions.remove(session);
	}

	@OnMessage
	public void echo(String message) throws IOException {
	for (Session session : sessions) {
	if (session.isOpen()) {
	log.info("{" + session.getId() + "} echo '" + message + "'");
	session.getBasicRemote().sendText(message);
	}
	}
	}

	}
	<!DOCTYPE html>
	<html>
	<head>
	<title>Echo</title>
	</head>
	<body>
	<input id="msg" type="text" />
	<button id="echo">Echo</button>
	<button id="close">Close</button>
	<ul id="area"></ul>
	<script>
	var area = document.getElementById("area");
	var msg = document.getElementById("msg");
	var ws = new WebSocket("ws://localhost:8080/echo");
	ws.onopen = function(event) {
	console.log(event);
	};
	ws.onclose = function(event) {
	console.log(event);
	};
	ws.onmessage = function(event) {
	console.log(event);
	var entry = document.createElement("li");
	entry.textContent = event.data;
	area.appendChild(entry);
	}
	ws.onerror = function(event) {
	console.log(event);
	}
	document.getElementById("echo").onclick = function() {
	ws.send(msg.value);
	};
	document.getElementById("close").onclick = function() {
	ws.close();
	};
	</script>
	</body>
	</html>
	<?xml version="1.0" encoding="UTF-8"?>
	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>jsr356-example</groupId>
	<artifactId>jsr356-example</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<properties>
	<encoding>UTF-8</encoding>
	<javaVersion>1.7</javaVersion>
	<jettyVersion>9.1.0.v20131115</jettyVersion><!-- 9.1.0+ -->
	<failOnMissingWebXml>false</failOnMissingWebXml>
	</properties>
	<dependencies>
	<dependency>
	<groupId>javax.websocket</groupId>
	<artifactId>javax.websocket-api</artifactId>
	<version>1.0</version>
	<scope>provided</scope>
	</dependency>
	</dependencies>
	<build>
	<plugins>
	<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-compiler-plugin</artifactId>
	<version>3.1</version>
	<configuration>
	<source>${javaVersion}</source>
	<target>${javaVersion}</target>
	<compilerVersion>${javaVersion}</compilerVersion>
	</configuration>
	</plugin>
	<plugin>
	<groupId>org.eclipse.jetty</groupId>
	<artifactId>jetty-maven-plugin</artifactId>
	<version>${jettyVersion}</version>
	<configuration>
	<reload>manual</reload>
	<systemProperties>
	<systemProperty>
	<name>java.util.logging.SimpleFormatter.format</name>
	<value>%1$tF %1$tT,%1$tL %4$s - %5$s%6$s%n</value>
	</systemProperty>
	</systemProperties>
	</configuration>
	</plugin>
	</plugins>
	</build>
	</project>