From http://stackoverflow.com/a/32393044/1305344:
object size extends App {
(1 to 1000000).map(i => ("foo"+i, ()))
val input = readLine("prompt> ")
}
Run it with sbt 'runMain size'
and then use jps
(to know the pids), jstat -gc pid
(to query for gc) and jmap
(similar to jstat
) to analise resource allocation.