My experience was the other way around Java => Perl, not liking it. I suppose people have different taste buds. While there are (small) values that one can get

My experience was the other way around Java => Perl, not liking it. I suppose people have different taste buds. While there are (small) values that one can get out of Java => Perl, being dynamic and functional, your experience seems seasonal (hashes, maps, etc). I felt that these days if one wants to learn algorithms and data structure, Java Collection libraries and Guava seem to be the defining standard. I don't disagree if one is learning Erlang to write scalable message queue coming from Rails. But I definitely disagree if one is learning another programming language and ended up coding the basic web-app, which seems to be the case these days.