code: private Set<EquivalenceDataIndex> stage2() {
          beginStage(PHASE2_STAGE2_HDR, "2", NUM_PHASES);
  
          Set<EquivalenceDataIndex> ret = new HashSet<EquivalenceDataIndex>();
  
          final StringBuilder bldr = new StringBuilder();
          bldr.append("Loading namespace equivalences from resource index");
          stageOutput(bldr.toString());
  
          long t1 = currentTimeMillis();
          try {
              ret.addAll(p2.stage2LoadNamespaceEquivalences());
          } catch (EquivalenceMapResolutionFailure e) {
              warning(e.getUserFacingMessage());
              // continue with an empty equivalence data index set
          }
  
          for (final EquivalenceDataIndex edi : ret) {
              final String nsLocation = edi.getNamespaceResourceLocation();
              bldr.setLength(0);
              bldr.append("Equivalence for ");
              bldr.append(nsLocation);
              stageOutput(bldr.toString());
          }
          long t2 = currentTimeMillis();
          bldr.setLength(0);
          markTime(bldr, t1, t2);
          markEndStage(bldr);
          stageOutput(bldr.toString());
          return ret;
      }
docs: Stage two equivalence loading, returning a set of data indices.
  
  @param equivalenceFile Equivalence file
  @return Set of equivalence data indices