Over a million developers have joined DZone.

Clojure/Java: Prevent Exceptions With "trace missing"

· Java Zone

Check out this 8-step guide to see how you can increase your productivity by skipping slow application redeploys and by implementing application profiling, as you code! Brought to you in partnership with ZeroTurnaround.

The other day I got this little helpful exception from Clojure:

(cond (>= nil 1) :unreachable)
;=> NullPointerException [trace missing]

- no line number or anything to troubleshoot it.

It turns out it is not Clojure’s failure but a HotSpot optimization that can apply to NullPointerExceptionArithmeticExceptionArrayIndexOutOfBoundsException,ArrayStoreException, and ClassCastException. The remedy is to run the JVM with

-XX:-OmitStackTraceInFastThrow

From Oralce JDK release notes:

The compiler in the server VM now provides correct stack backtraces for all “cold” built-in exceptions. For performance purposes, when such an exception is thrown a few times, the method may be recompiled. After recompilation, the compiler may choose a faster tactic using preallocated exceptions that do not provide a stack trace. To disable completely the use of preallocated exceptions, use this new flag: -XX:-OmitStackTraceInFastThrow.

Many thanks to Ivan Kozik for the info!

The Java Zone is brought to you in partnership with ZeroTurnaround. Check out this 8-step guide to see how you can increase your productivity by skipping slow application redeploys and by implementing application profiling, as you code!

Topics:

Published at DZone with permission of Jakub Holý, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

The best of DZone straight to your inbox.

SEE AN EXAMPLE
Please provide a valid email address.

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.
Subscribe

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}