Logstash's default max heap size

To know Logstash's default max heap size, use `jps -v` as follows:

$ jps -v
15396 Main -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -Djava.awt.headless=true -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+HeapDumpOnOutOfMemoryError -Xmx1g -Xss2048k -Djffi.boot.library.path=/home/izeye/programs/logstash-2.3.4/vendor/jruby/lib/jni -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -Djava.awt.headless=true -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/izeye/programs/logstash-2.3.4/heapdump.hprof -Xbootclasspath/a:/home/izeye/programs/logstash-2.3.4/vendor/jruby/lib/jruby.jar -Djruby.home=/home/izeye/programs/logstash-2.3.4/vendor/jruby -Djruby.lib=/home/izeye/programs/logstash-2.3.4/vendor/jruby/lib -Djruby.script=jruby -Djruby.shell=/bin/sh
15460 Jps -Dapplication.home=/home/izeye/programs/jdk1.8.0_45 -Xms8m
$

You can see `-Xmx1g` (ie. 1GB).

The result is from Logstash 2.3.4.