Create GXT 3 project example

Here is the way you could create GXT 3 project.
You would use Maven Archetype with a little workaround of pom.xml and code.

Form CLI execute:

mvn archetype:generate    -DarchetypeGroupId=org.codehaus.mojo    -DarchetypeArtifactId=gwt-maven-plugin    -DarchetypeVersion=2.7.0

Then:

mvn gwt:verify

mvn gwt:run

At this point you will be able to run pure GWT demo.

Now is the GXT time:

In root html file add following line as the first stylesheet

<link rel="stylesheet" type="text/css" href="MyModule/reset.css">

Remove the table for the Web Application Starter project. We don’t need it for this guide.

Add the line below to the *.gwt.xml
<inherits name="com.sencha.gxt.ui.GXT" />
And remove the following line from the same file:
<inherits name="com.google.gwt.user.theme.standard.Standard" />

Inside of the main root class that implements EntryPoint leave only this:

public void onModuleLoad() {
    BasicTabExample tabs = new BasicTabExample();
    RootPanel.get().add(tabs);
}

Create in the same package of the root class this class:

How to install Apache Tomcat Server on Ubuntu

Here is the simplest way to install Tomcat 7 on Linux Ubuntu 14.04

Execute these commands from terminal

sudo apt-get update
sudo apt-get install tomcat7

Try run:
sudo /usr/share/tomcat7/bin/startup.sh 

If you've got an error do this:
sudo dpkg-reconfigure tomcat7

Can't run Tomcat from Intellij Idea?

cd /usr/share/tomcat7 

ln -s /etc/tomcat7 conf 

chmod -R 655 /etc/tomcat7/