code: public static String buildOwnerId( RecipientKind ownerKind, String applicationName, String scopedInstancePath ) {
  
  		StringBuilder sb = new StringBuilder();
  		if( ownerKind == RecipientKind.DM ) {
  			sb.append( "@DM@" );
  
  		} else {
  			if( scopedInstancePath !=null ) {
  				sb.append( scopedInstancePath );
  				sb.append( " " );
  			}
  
  			if( applicationName != null ) {
  				sb.append( "@ " );
  				sb.append( applicationName );
  			}
  		}
  
  		// The "domain" is not used here.
  		// "domain" was not designed for self-hosted messaging but for "real" messaging servers.
  		return sb.toString().trim();
  	}
docs: Builds a unique ID.
  @param ownerKind the owner kind (not null)
  @param applicationName the application name (can be null)
  @param scopedInstancePath the scoped instance path (can be null)
  @return a non-null string