I found the following entry on my classpath
.sdkman/grails/2.5.0/lib/com.google.guava/guava/jars/guava-10.0.1.jar
before entry :
Users/luukdaemen/.m2/repository/com/google/guava/guava/18.0/guava-18.0.jar
This is probably causing it.
How can i exclude the old library from the class path, related to the build.groovy ?