The certificate required for the tests was created like this:
openssl genrsa -out server.key 4096
openssl req -new -sha256 -key server.key -out server.csr \
-subj "/C=BE/L=Brussels/O=Eclipse Foundation/OU=Eclipse Glassfish/CN=localhost"
openssl x509 -req -sha256 -days 3650 -in server.csr -signkey server.key -out server.crt
openssl pkcs12 -in server.crt -inkey server.key -export -out server.p12 -name s1as -password pass:changeit
keytool -importkeystore \
-srckeystore server.p12 -srcstoretype PKCS12 -srcstorepass changeit \
-destkeystore keystore.jks -deststorepass changeit
keytool -import -noprompt -keystore cacerts.jks -storepass changeit -alias s1as -file server.crt