docs: private static Long getUpdatedStamp(String absPath, File file) {
          String methodName = "getUpdatedStamp";
          boolean doDebug = tc.isDebugEnabled();
  
          Long currentStamp = Long.valueOf( file.lastModified() );
  
          Long newStamp;
          String newStampReason = null;
  
          synchronized ( expansionStamps ) {
              Long priorStamp = expansionStamps.put(absPath, currentStamp);
  
              if ( priorStamp == null ) {
                  newStamp = currentStamp;
                  if ( doDebug ) {
                      newStampReason = "First extraction; stamp [ " + currentStamp + " ]";
                  }
              } else if ( currentStamp.longValue() != priorStamp.longValue() ) {
                  newStamp = currentStamp;
                  if ( doDebug ) {
                      newStampReason = "Additional extraction; old stamp [ " + priorStamp + " ] new stamp [ " + currentStamp + " ]";
                  }
              } else {
                  newStamp = null;
                  if ( doDebug ) {
                      newStampReason = "No extraction; stamp [ " + currentStamp + " ]";
                  }
              }
          }
  
          if ( doDebug ) {
              Tr.debug(tc, methodName + ": " + newStampReason);
          }
          return newStamp;
      }