Enable G1's String Deduplication by default.

[Laszlo Kishalmi <la...@gmail.com>]

Dear all,


I've opened an issue months ago in order to revisit the default startup 
options. https://issues.apache.org/jira/browse/NETBEANS-342

I did not came up with anything really big, besides removing the client 
VM specification. However I think we can add string deduplication 
feature of G1 GC (-XX:+UseStringDeduplication), which is available since 
JVM 1.8.0_20.

Honestly I used NetBeans with that for years and I did not notice any 
drawbacks of that so far. What I noticed, when I started to use theSnap 
packages I'm building for Linux, is that NetBeans is a bit more power 
hungry when I working on NB modules. This meant that my 1 Gb heap was 
almost fully consumed when module indexing/parsing happened and forced 
the IDE to more garbage collecting. Re-enabling String deduplication 
helped a lot.

String Deduplication feature has been available since 2014 and even 
Eclipse is using that option from 2016. I think it is safe to enable it 
for 9.0.

See: https://github.com/apache/incubator-netbeans/pull/518

What do you think?