Deploy WAR on Tomcat 7 exception

Question

I am just starting to learn Spring Boot and followed the example for a RESTful service, the typical Greeting (Hello World). The example runs fine as a JAR or as a WAR within Eclipse and Tomcat 7 when I build as a Java application. I then use maven build with package as a goal and whenever I copy the WAR on my local Tomcat 7 webapps directory I can see on the console exceptions such as this one:

SEVERE: ContainerBase.addChild: start: 
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/demo-0.0.1]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1081)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1877)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String;
    at org.apache.tomcat.websocket.server.WsServerContainer.<init>(WsServerContainer.java:147)
    at org.apache.tomcat.websocket.server.WsSci.init(WsSci.java:131)
    at org.apache.tomcat.websocket.server.WsSci.onStartup(WsSci.java:47)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5513)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 10 more

Mar 18, 2015 10:38:24 PM org.apache.catalina.startup.HostConfig deployWAR
SEVERE: Error deploying web application archive /Users/tester/Servers/apache-tomcat-7.0.59/webapps/demo-0.0.1.war
java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/demo-0.0.1]]
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:904)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1081)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1877)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)

Any ideas as to what is happening?

I followed this link to build and deploy my code: http://spring.io/blog/2014/03/07/deploying-spring-boot-applications