WildFly 10 — java.lang.OutOfMemoryError: Metadata space

Occasionally, during development, WildFly seems to chew up its Metadata space. For me this seems to happen when I am deploying and undeploying an application often on my workstation during development. I find it useful to edit the standalone.conf file in the bin directory of my local wildfly install and give the application server a little more breathing room with regard to memory. I make the following edit around line 50 of this file:

Change:
JAVA_OPTS=”-Xms64m -Xmx512m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -Djava.net.preferIPv4Stack=true”

To:
JAVA_OPTS=”-Xms64m -Xmx2G -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=2G -Djava.net.preferIPv4Stack=true”

I’m using JDK 8 so the JDK 8 HotSpot JVM is now using native memory for the representation of class metadata and is called Metaspace.

And, yes, 2G above is probably overkill. Tune to your needs and available RAM on your workstation.