question: public TrustSource add ( File trustedCAPemFile ) { if ( trustedCAPemFile == null ) { throw new IllegalArgumentException ( "Trusted CA file cannot be null" ) ; } String pemFileContents ; try { pemFileContents = Files . toString ( trustedCAPemFile , Charset . forName ( "UTF-8" ) ) ; } catch ( IOException e ) { throw new UncheckedIOException ( "Unable to read file containing PEM-encoded trusted CAs: " + trustedCAPemFile . getAbsolutePath ( ) , e ) ; } return add ( pemFileContents ) ; }
target:  Returns a new TrustSource containing the same trusted CAs as this TrustSource, plus zero or more CAs contained in the PEM-encoded File. The File may contain multiple certificates and may contain comments or other non-PEM-encoded text, as long as the PEM-encoded certificates are delimited by appropriate BEGIN_CERTIFICATE and END_CERTIFICATE text blocks. The file may contain UTF-8 characters, but the PEM-encoded certificate data itself must be US-ASCII.