Cannot open a Memcached cache settings in Lucee Administrator

I’ve got a couple Memcached caches that I created in .CFConfig.json that I cannot view in the Lucee Administrator. When I try to open either of the cache settings, I get the error:

Cannot invoke “java.util.List.size()” because the return value of “lucee.commons.io.cache.Cache.keys()” is null

I tried to create a brand new Memcached cache through the administrator, and I still cannot open the settings page for it.

I’m running Memcached extension: org.lucee.memcached.extension (4.0.0.14)

The Lucee stack trace (this is really interesting!):

The Error Occurred in
/admin/services.cache.create.cfm: line 79
called from /admin/services.cache.cfm: line 41
called from /admin/web.cfm: line 521
called from /admin/web.cfm: line 515
called from /var/my-app/www/admin/index.cfm: line 3

Notice the bottom line in the stack trace. I put in “my-app” as a placeholder, but it really is the path to the app I’m running, and that directory does exist. I suspect this could be part of the problem.

In addition, the Java stacktrace is:

lucee.runtime.exp.NativeException: Cannot invoke "java.util.List.size()" because the return value of "lucee.commons.io.cache.Cache.keys()" is null
 at lucee.runtime.functions.cache.CacheCount.call(CacheCount.java:42)
 at services_cache_create_cfm1104$cf.call(/admin/services.cache.create.cfm:79)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1118)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1012)
 at lucee.runtime.PageContextImpl.doInclude(PageContextImpl.java:993)
 at services_cache_cfm414$cf.call(/admin/services.cache.cfm:41)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1118)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1012)
 at lucee.runtime.PageContextImpl.doInclude(PageContextImpl.java:993)
 at web_cfm$cf.call_000007(/admin/web.cfm:521)
 at web_cfm$cf.call(/admin/web.cfm:515)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1118)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1012)
 at lucee.runtime.PageContextImpl.doInclude(PageContextImpl.java:993)
 at index_cfm$cf.call(/admin/index.cfm:3)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1118)
 at lucee.runtime.PageContextImpl._doInclude(PageContextImpl.java:1012)
 at lucee.runtime.listener.ModernAppListener._onRequest(ModernAppListener.java:215)
 at lucee.runtime.listener.ModernAppListener.onRequest(ModernAppListener.java:102)
 at lucee.runtime.PageContextImpl.execute(PageContextImpl.java:2816)
 at lucee.runtime.PageContextImpl._execute(PageContextImpl.java:2803)
 at lucee.runtime.PageContextImpl.executeCFML(PageContextImpl.java:2774)
 at lucee.runtime.engine.Request.exe(Request.java:45)
 at lucee.runtime.engine.CFMLEngineImpl._service(CFMLEngineImpl.java:1113)
 at lucee.runtime.engine.CFMLEngineImpl.serviceCFML(CFMLEngineImpl.java:1070)
 at lucee.loader.engine.CFMLEngineWrapper.serviceCFML(CFMLEngineWrapper.java:97)
 at lucee.loader.servlet.jakarta.CFMLServlet.service(CFMLServlet.java:52)
 at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:710)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:128)
 at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:107)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:165)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:77)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:113)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:83)
 at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:685)
 at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:654)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:72)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:341)
 at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:397)
 at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
 at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:903)
 at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1801)
 at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
 at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:946)
 at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:480)
 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:57)
 at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.NullPointerException: Cannot invoke "java.util.List.size()" because the return value of "lucee.commons.io.cache.Cache.keys()" is null
 ... 49 more

OS: Ubuntu 24.04 (Noble)
Java: OpenJDK 21
Tomcat Version: 11.0.6
Lucee Version: 6.2.6.19
Memcached: org.lucee.memcached.extension (4.0.0.14)