I keep seeing plenty of evidence that the JVM is indeed heavy. When I was working at a startup and we were running Solr on the JVM, it kept running out of memory and crashing. When I tried using Clojure I was irritated by the startup time of the REPL on the JVM. More evidence: http://stackoverflow.com/questions/13692206/high-java-memory....
If you want something light not like Clojure, Go is a great choice. It's fast to compile, fast to run and doesn't gobble up your memory unless you force it to.
If you ran a game written in C++ that kept running out of memory and crashing, would you say C++ is "heavy"? Solr (and Lucene internally) maintain large in-memory data structures as well as memory map (usually) on-disk segment files. How much memory they use is determined by many, many configuration options within Solr. This has nothing to do with the JVM.
Same thing with Clojure. It basically bootstraps the entire Clojure environment on each process start. The JVM itself starts up in tens of milliseconds.
If you want something light like Clojure and don't need any Java libs, try Pixie. https://github.com/pixie-lang/pixie
If you want something light not like Clojure, Go is a great choice. It's fast to compile, fast to run and doesn't gobble up your memory unless you force it to.