code: public void addSingleton(BeanMetaData bmd, boolean startup, Set<String> dependsOnLinks) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
              Tr.debug(tc, "addSingleton: " + bmd.j2eeName + " (startup=" + startup + ", dependsOn=" + (dependsOnLinks != null) + ")");
  
          if (startup) {
              if (ivStartupSingletonList == null) {
                  ivStartupSingletonList = new ArrayList<J2EEName>();
              }
              ivStartupSingletonList.add(bmd.j2eeName);
          }
  
          if (dependsOnLinks != null) {
              if (ivSingletonDependencies == null) {
                  ivSingletonDependencies = new LinkedHashMap<BeanMetaData, Set<String>>();
              }
              ivSingletonDependencies.put(bmd, dependsOnLinks);
          }
      }
docs: Adds a singleton bean belonging to this application.
  
  @param bmd
  the bean metadata
  @param startup
  true if this is a startup singleton bean
  @param dependsOnLinks
  list of dependency EJB links