code: @Override
      public boolean isOutdated() {
          File nullSourceFile = null;
          Entry containerEntry = inputSource.getInputSourceEntry();
          Entry webinfClassEntry = container.getEntry(webinfClassRelativeUrl);
          
          //If the inputSource is not a container entry
          if(containerEntry == null){
              long lastModified = inputSource.getLastModified();
              return ResourceUtil.isOutdated(lastModified, null, nullSourceFile, generatedSourceFile, classFile, webinfClassEntry, null);
          }
          return ResourceUtil.isOutdated(containerEntry, nullSourceFile, generatedSourceFile, classFile, webinfClassEntry, null);
      }
docs: {@inheritDoc}