Server-side JSSE now operates in stateless mode by default. As described in RFC 5077[1] for TLS 1.2 and below, and RFC 8446[2] for TLS 1.3, the TLS server sends internal session information in the form of an encrypted session ticket to a client that supports stateless. That session ticket is presented to the server during the TLS handshake to resume the session. This should improve the performance and memory usage of the TLS server under large workloads as the session cache will seldom be used. Applications that depend on SSLSession to list sessions cached will not find that information in stateless mode.

If stateless needs to be turned off, use the System property `jdk.tls.server.enableSessionTicketExtension`. Using `-Djdk.tls.server.enableSessionTicketExtension=false` on the command-line will turn off stateless and return the JSSE server to using the session cache.


[1]: https://tools.ietf.org/html/rfc5077
[2]: https://tools.ietf.org/html/rfc8446