@Override
 public int hashCode() {
   final int prime = 31;
   int result = 1;
   result = prime * result + ((container == null) ? 0 : container.hashCode());
   return result;
 }
 @Override
 public boolean equals(Object obj) {
   if (this == obj) return true;
   if (obj == null) return false;
   if (getClass() != obj.getClass()) return false;
   DockerContainerVolumesCategory other = (DockerContainerVolumesCategory) obj;
   if (container == null) {
     if (other.container != null) return false;
   } else if (!container.equals(other.container)) return false;
   return true;
 }