question: public BurpCertificate importCertificate ( String filename ) { setStatus ( "Importing certificate..." ) ; FileInputStream fis ; try { fis = new FileInputStream ( filename ) ; byte value [ ] = new byte [ fis . available ( ) ] ; fis . read ( value ) ; ByteArrayInputStream bais = new ByteArrayInputStream ( value ) ; fis . close ( ) ; CertificateFactory certFactory = CertificateFactory . getInstance ( "X.509" ) ; X509Certificate x509certificate = ( X509Certificate ) certFactory . generateCertificate ( bais ) ; BurpCertificate certificate = new BurpCertificate ( x509certificate ) ; certificate . setPublicKey ( x509certificate . getPublicKey ( ) ) ; certificate . setSource ( "Imported" ) ; burpCertificateStore . addCertificate ( certificate ) ; setCertificateTree ( ) ; setStatus ( "Certificate imported." ) ; setCertificateDetails ( certificate ) ; return certificate ; } catch ( IOException | CertificateException e ) { setStatus ( "Error reading file. (" + e . getMessage ( ) + ")" ) ; e . printStackTrace ( ) ; } catch ( Exception e ) { setStatus ( "Error (" + e . getMessage ( ) + ")" ) ; e . printStackTrace ( ) ; } return null ; }
target:  Read an X.509v3 certificate from a file.