Netbeans jUnit 4 - Java EE API is missing on project classpath - maven

Question

I have clear maven web app project.
I add jUnit to pom.
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
<dependency>
<!-- jsoup HTML parser library # http://jsoup.org/ -->
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>1.7.2</version>
</dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>6.0</version>
</dependency>
</dependencies>
I have one very simple Servlet in my app.
I want to generate jUnit 4 test for this servlet.
So I click on the Servlet package > Tools > Create Test.
After this I get test class with method.
public void testProcessRequest() throws Exception {
System.out.println("processRequest");
HttpServletRequest request = null;
HttpServletResponse response = null;
MyServlet instance = new MyServlet(); // This is the problem
instance.processRequest(request, response);
// TODO review the generated test code and remove the default call to fail.
//fail("The test case is a prototype.");
}
MyServlet is underline and the error is : "Java EE API is missing on the project classpath".
I tried modify the scopes of dependencies in pom but problem still exist.