http://community.jboss.org/wiki/GeneratingSelfSignedCertificateWithKeytool
Generating Self Signed Certificate with Keytool

Creating private/public key pair:
keytool -genkey -alias ... -keyalg RSA -validity 365 -keystore server.keystore -storetype JKS

Extracting the public key:
keytool -export -alias ... -keystore server.keystore -rfc -file public.cert

Creating the Truststore:
keytool -import -alias ... -file public.cert -storetype JKS -keystore server.truststore