Gradle configuration strips off JPA Annotations

gistfile1.txt

task serverJar(type: Jar) {
    classifier = 'server'
    from sourceSets.main.output
}

task removeAnnotation << {

    ant.echo("strip annotation")

    ant.taskdef(resource: 'org/dyndns/fichtner/purgeannotationrefs/tasks/antlib.xml') {
        classpath {
            fileset(dir: '../app/ant/par_ant-0.3.1', includes: '*.jar')
        }
    }
    println sourceSets.main.output.classesDir
    ant.purgeannotationrefs() {
        src {
            fileset(dir: sourceSets.main.output.classesDir)
        }
        remove(annotation: "javax.persistence.Entity")
        remove(annotation: "javax.persistence.MappedSuperclass")
        remove(annotation: "javax.persistence.Column")
        remove(annotation: "javax.persistence.Id")
        remove(annotation: "javax.persistence.GeneratedValue")
        remove(annotation: "javax.persistence.Transient")
        remove(annotation: "javax.persistence.ManyToOne")
        remove(annotation: "javax.persistence.OneToMany")
        remove(annotation: "javax.persistence.OneToOne")
        remove(annotation: "javax.persistence.ElementCollection")
        remove(annotation: "javax.persistence.Embeddable")
        remove(annotation: "javax.persistence.PrePersist")
        remove(annotation: "javax.persistence.PreUpdate")
    }
    ant.echo("end strip annotation")
}

serverJar.dependsOn classes
removeAnnotation.dependsOn serverJar

jar {
    dependsOn removeAnnotation
    classifier = 'client'
    from(sourceSets.main.output)
    exclude('android/**/*')
}

artifacts {
    archives jar
    archives serverJar
}