In ZK 3.4.x, if the client disconnects unexpectedly then the server logs this with a stack-trace (see src/java/main/org/apache/zookeeper/server/NIOServerCnxn.java:356).
This is unfortunate as we are using an embedded ZK server in our project (in a test environment) and we consider all stack-traces as bugs.
I noticed that ZK 3.5 and later no longer log a stack-trace. This change is due to commit 6206b495 (in branch-3.5), which adds
ZOOKEEPER-1504 and seems to fix this issue almost as a side-effect; a similar change in master has the same effect.
I was wondering if the change in how EndOfStreamException is logged (i.e., logging the message without a stack-trace) could be back-ported to 3.4 branch, so could be included in the next 3.4 release.