[bjoernbu]

The HN headline is somewhat misleading. It is different from the original article and I was expecting some neat techniques to overcome the typical memory issues:

Everything is an object, generics need wrapper classes, padding everywhere. Those make HashMap<Integer>, ArrayList<Integer> or even "two dimensional arrays" a bad joke compared to C(++) equivalents. Projects like Lucene have to rewrite standard library eqiuvalents for specific cases since otherwise so much performance would be lost.

Examinating app server -Xmx settings is more handwaving than anything. Especially people that refrain from doing certain things in java due to memory issues, have a completely misleading influence on such a metric.