I\'ve heard of Java programs with strict latency requirements where \"new\" instructions are never -or very rarely- used (because no new=>no objects->no GC=>improved latency
There might be some trading systems that do this, but from my understanding (My colleagues work in Java based low-latency trading platforms) a good fast modern JVM combined with sensible coding practice removes the need to go for 'pure primitives' in code. That said I'm not a low-latency developer, our middleware team only worries about 1,000's of txn's per minute, not 10,000's+. Can't say I've found a convincing article on this, although I'm happy to be pleasantly surprised :)