Solution: In "EmbeddedJettyServer" I changed
"MAPPING_URL" to "/".
"ServletContextHandler" to "WebAppContext"
Added missin dependency in pom:
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-jsp</artifactId>
<version>9.2.0.M0</version>
</dependency>
Also had to configure IDE to use JDK instead of JRE