code: public final Collection<SNIMatcher> getSNIMatchers() {
          if (sniMatchers != null) {
              if (!sniMatchers.isEmpty()) {
                  return Collections.<SNIMatcher>unmodifiableList(
                                          new ArrayList<>(sniMatchers.values()));
              } else {
                  return Collections.<SNIMatcher>emptyList();
              }
          }
  
          return null;
      }
docs: Returns a {@link Collection} containing all {@link SNIMatcher}s of the
  Server Name Indication (SNI) parameter, or null if none has been set.
  <P>
  This method is only useful to {@link SSLSocket}s or {@link SSLEngine}s
  operating in server mode.
  <P>
  For better interoperability, providers generally will not define
  default matchers so that by default servers will ignore the SNI
  extension and continue the handshake.
  
  @return null or an immutable collection of non-null {@link SNIMatcher}s
  
  @see SNIMatcher
  @see #setSNIMatchers(Collection)
  
  @since 1.8