question: private List < List < DimensionIndex > > populateHierarchy ( Space space , List < Dimension > dims ) throws InterruptedException { List < List < DimensionIndex > > result = new ArrayList < > ( ) ; for ( Dimension dimension : dims ) { logger . info ( "populateHierarchy " + dimension . toString ( ) ) ; if ( dimension . getParentId ( ) == null ) { Axis axis = space . A ( dimension ) ; List < DimensionIndex > hierarchy = populateHierarchy ( space , null , null , axis ) ; if ( ! hierarchy . isEmpty ( ) ) { result . add ( hierarchy ) ; } } } return result ; }
target:  populate the hierarchy from a base Space