不一定是在Maven Projects里才有这种情况，但解决方法是一样的。
转自:http://qussay.com/2013/09/13/solving-dynamic-web-module-3-0-requires-java-1-6-or-newer-in-maven-projects/
Solving “Dynamic Web Module 3.0 requires Java 1.6 or newer” in Maven Projects
First check that your project is configured probably to use Java 1.6或以上
Right click your project > Properties > Java Compiler and set “Compiler compliance level” to 1.6或以上
Next from the menu on the left select Project Facets > Java and set its version to 1.6或以上
