JAXB task in gradle

build.gradle

def generatedResources = "src/main/generated-sources"

task jaxb(){
	description 'Converts xsds to classes'
	def jaxbTargetDir = file( generatedResources )
    jaxbTargetDir.deleteDir()
	
    doLast {
        jaxbTargetDir.mkdirs()

        ant.taskdef(name: 'xjc', classname: 'com.sun.tools.xjc.XJCTask', classpath: configurations.jaxb.asPath)
        ant.jaxbTargetDir = jaxbTargetDir
        
        ant.xjc(destdir: '${jaxbTargetDir}', package: 'com.thehutgroup.xml.representation') {
                schema(dir:'XSD/Representation', includes: '*.xsd')
        }
        
        ant.xjc(destdir: '${jaxbTargetDir}', package: 'com.thehutgroup.xml.event') {
                schema(dir:'XSD/Event', includes: '*.xsd')
        }
    }
}

task generateSources(dependsOn: jaxb) {
	description 'generates the resources defined by the external xsd\'s'
}

Found your blog post while searching for a fix for the compile issue. I'll link it here in case anyone else runs into it:
http://squidoop.blogspot.com/2012/11/jaxb-generation-using-gradle.html