question: public void encode ( OutputStream out ) throws IOException { if ( notBefore == null || notAfter == null ) { throw new IOException ( "CertAttrSet:CertificateValidity:" + " null values to encode.\n" ) ; } DerOutputStream pair = new DerOutputStream ( ) ; if ( notBefore . getTime ( ) < YR_2050 ) { pair . putUTCTime ( notBefore ) ; } else pair . putGeneralizedTime ( notBefore ) ; if ( notAfter . getTime ( ) < YR_2050 ) { pair . putUTCTime ( notAfter ) ; } else { pair . putGeneralizedTime ( notAfter ) ; } DerOutputStream seq = new DerOutputStream ( ) ; seq . write ( DerValue . tag_Sequence , pair ) ; out . write ( seq . toByteArray ( ) ) ; }
target:  Encode the CertificateValidity period in DER form to the stream.