I will maven a new project first.
Select webapp,

buildpath is changed from jdk1.5 to 1.8,
modified org.eclipse.wst.common.project.facet.core.xml

< installed facet= "jst.web" version= "4.0" / >
< installed facet=" wst.jsdt.web "version=" 1.0" / >
< installed facet= "java" version= "1.8" / >

pom.xml

added

< plugins >
< plugin >
< groupId > org.apache.maven.plugins < / groupId >
maven-compiler-plugin < / artifactId >
< configuration >
< source > 1.8 < / source >
< target > 1.8 < / target >
< / configuration >
< / plugin >
< / plugins >

at the same time Projects Facets
selected
Java 1.8
Dynamic Web Module 4.0

web.xml
is this

< web-app xmlns:xsi= " http://www.w3.org/2001/XMLSch...; xmlns= " http://java.sun.com/xml/ns/ja...; Xsi:schemaLocation= " http://java.sun.com/xml/ns/ja... http://java.sun.com/xml/ns/javaee/web-app_4_0.xsd" id= "WebApp_ID" version= "4.0" >
< display-name > Archetype Created Web Application < / display-name >
< / web-app >

and then he kept validating without saying anything wrong. What"s wrong with it?