High load at idle?

[cinterloper]

when running log4j in debug mode; and Zookeeper running in the same JVM as vertx i get an absurdly fast stream of the following message pattern:

2016-04-13 17:30:52,061 - DEBUG [SyncThread:0:FinalRequestProcessor@160] - sessionid:0x154122d2de10000 type:exists cxid:0xfd98 zxid:0xfffffffffffffffe txntype:unknown reqpath:/io.vertx/asyncMultiMap/__vertx.subs
2016-04-13 17:30:52,061 - DEBUG [SyncThread:0:FinalRequestProcessor@88] - Processing request:: sessionid:0x154122d2de10000 type:exists cxid:0xfd99 zxid:0xfffffffffffffffe txntype:unknown reqpath:/io.vertx/asyncMultiMap/__vertx.subs
2016-04-13 17:30:52,061 - DEBUG [vert.x-worker-thread-0-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@818] - Reading reply sessionid:0x154122d2de10000, packet:: clientPath:/io.vertx/asyncMultiMap/__vertx.subs serverPath:/io.vertx/asyncMultiMap/__vertx.subs finished:false header:: 64920,3  replyHeader:: 64920,184,-101  request:: '/io.vertx/asyncMultiMap/__vertx.subs,T  response::  
2016-04-13 17:30:52,061 - DEBUG [SyncThread:0:FinalRequestProcessor@160] - sessionid:0x154122d2de10000 type:exists cxid:0xfd99 zxid:0xfffffffffffffffe txntype:unknown reqpath:/io.vertx/asyncMultiMap/__vertx.subs

The machine idles at around 100% cpu load for 1 core

[cinterloper]

this also happens with zookeeper in a different jvm