question: public void requestContactCapabilities ( Set < ContactId > contacts ) throws RcsServiceNotRegisteredException , RcsServiceNotAvailableException , RcsGenericException { if ( mApi == null ) { throw new RcsServiceNotAvailableException ( ) ; } if ( contacts == null || contacts . isEmpty ( ) ) { throw new RcsIllegalArgumentException ( "contacts must not be null or empty!" ) ; } try { mApi . requestContactCapabilities2 ( new ArrayList < > ( contacts ) ) ; } catch ( Exception e ) { RcsIllegalArgumentException . assertException ( e ) ; RcsServiceNotRegisteredException . assertException ( e ) ; throw new RcsGenericException ( e ) ; } }
target:  Requests capabilities for a group of remote contacts. This method initiates in background new capability requests to the remote contact by sending a SIP OPTIONS. The result of the capability request is sent asynchronously via callback method of the capabilities listener. The parameter contacts supports the following formats: MSISDN in national or international format, SIP address, SIP-URI or Tel-URI. If the format of the contact is not supported an exception is thrown. The result of the capability refresh request is provided to all the clients that have registered the listener for this event.