code: public static ResourceBundle getBundle(String baseName, Locale locale) {
  
          // If the default locale changed since the last time we were called,
          // all cache entries are invalidated.
          Locale defaultLocale = Locale.getDefault();
          if (defaultLocale != m_lastDefaultLocale) {
              synchronized (m_bundleCache) {
                  if (defaultLocale != m_lastDefaultLocale) {
                      m_bundleCache = new ConcurrentHashMap<BundleKey, ResourceBundle>();
                      m_lastDefaultLocale = defaultLocale;
                  }
              }
          }
  
          // This will throw NullPointerException if any arguments are null.
          BundleKey m_lookupKey = new BundleKey(baseName, locale);
  
          Object obj = m_bundleCache.get(m_lookupKey);
  
          if (obj instanceof ResourceBundle) {
              return (ResourceBundle)obj;
          } else if (obj == NULL_ENTRY) {
              // Lookup has failed previously. Fall through.
          } else {
              synchronized (m_bundleCache) {
                  obj = m_bundleCache.get(m_lookupKey);
                  if (obj instanceof ResourceBundle) {
                      // check the bundle again
                      return (ResourceBundle)obj;
                  }
                  // First, look for a bundle for the specified locale. We don't want
                  // the base bundle this time.
                  boolean wantBase = locale.equals(m_lastDefaultLocale);
                  ResourceBundle bundle = tryBundle(baseName, locale, wantBase);
  
                  // Try the default locale if necessary
                  if ((bundle == null) && !locale.equals(m_lastDefaultLocale)) {
                      bundle = tryBundle(baseName, m_lastDefaultLocale, true);
                  }
  
                  BundleKey key = new BundleKey(baseName, locale);
                  if (bundle != null) {
                      // Cache the result and return it.
                      m_bundleCache.put(key, bundle);
                      return bundle;
                  }
              }
          }
  
          // unable to find the resource bundle with this implementation
          // use default Java mechanism to look up the bundle again
          return ResourceBundle.getBundle(baseName, locale);
      }
docs: handled.