NullPointerException while adding a Maven 2 project if there is already an Ant project in the group

This occurs in the Selenium test:testAddMavenTwoProjectFromRemoteSourceToNonDefaultProjectGroup

java.lang.NullPointerException
at org.apache.maven.continuum.DefaultContinuum.checkForDuplicateProjectInGroup(DefaultContinuum.java:3750)
at org.apache.maven.continuum.DefaultContinuum.executeAddProjectsFromMetadataActivity(DefaultContinuum.java:1714)
at org.apache.maven.continuum.DefaultContinuum.executeAddProjectsFromMetadataActivity(DefaultContinuum.java:1843)
at org.apache.maven.continuum.DefaultContinuum.addMavenTwoProject(DefaultContinuum.java:1393)
at org.apache.maven.continuum.web.action.AddMavenTwoProjectAction.doExecute(AddMavenTwoProjectAction.java:109)
at org.apache.maven.continuum.web.action.AddMavenProjectAction.execute(AddMavenProjectAction.java:189)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267)
at org.apache.struts2.interceptor.BackgroundProcess$1.run(BackgroundProcess.java:56)
at java.lang.Thread.run(Thread.java:637)