code: protected void readESJPClasses()
          throws InstallationException
      {
          try  {
              final QueryBuilder queryBldr = new QueryBuilder(this.classType);
              final MultiPrintQuery multi = queryBldr.getPrint();
              multi.addAttribute("Name");
              multi.executeWithoutAccessCheck();
              while (multi.next()) {
                  final String name = multi.<String>getAttribute("Name");
                  final Long id = multi.getCurrentInstance().getId();
                  this.class2id.put(name, id);
              }
          } catch (final EFapsException e) {
              throw new InstallationException("Could not fetch the information about compiled ESJP's", e);
          }
      }
docs: All stored compiled ESJP's classes in the eFaps database are stored in
  the mapping {@link #class2id}. If a ESJP's program is compiled and
  stored with {@link ESJPCompiler.StoreObject#write()}, the class is
  removed. After the compile, {@link ESJPCompiler#compile(String)} removes
  all stored classes which are not needed anymore.
  
  @throws InstallationException if read of the ESJP classes failed
  @see #class2id