- download the certificate by browser;
- import it by keytool
keytool -import -alias aliasName -keystore cacerts -file fileName -storepass changeit -trustcacerts -noprompt Certificate was added to keystore
- get certificate by java source code: https://github.com/escline/InstallCert/blob/master/InstallCert.java
http://www.xinotes.net/notes/note/1088/
TU.addCertificationForURL(url);