This is reported by Yoshiaki Takahashi. It is a similar issue as
HADOOP-11368 and YARN-5309 in URLConnectionFactory.
SSLFactory in newSslConnConfigurator and subsequently creates the ReloadingX509TrustManager instance which in turn starts a trust store reloader thread.
However, the SSLFactory is never destroyed and hence the trust store reloader threads are not killed.
We observed many leaked threads when we used swebhdfs via NiFi cluster.
"Truststore reloader thread" Id=221 TIMED_WAITING on null
at java.lang.Thread.sleep(Native Method)