When I build a fresh hs-rt cloned repository and try to run the JCKs as I used to:

setenv http_proxy www-proxy.us.oracle.com:80
set el = <some path starting with /java>/promoted/latest/extra/kfl/jck9.kfl
set jt = <some path starting with /java>promoted/latest/binaries/JCK-runtime-9/lib/jtjck.jar

java -jar $jt -headless -v -jdk $JAVA_HOME -exclude $el vm

I get:
philli% java -jar $jt -headless -v -jdk $JAVA_HOME -exclude $el vm
WARNING: missing resource: notification.logname for com.sun.javatest.i18n
WARNING: missing resource: logger.logfile.name for com.sun.javatest.logging.i18n
WARNING: missing resource: logger.logfile.ext for com.sun.javatest.logging.i18n
WARNING: missing resource: cc.verbose.name for com.sun.javatest.tool.i18n
WARNING: missing resource: cc.verbose.desc for com.sun.javatest.tool.i18n
WARNING: missing resource: verb.max.name for com.sun.javatest.tool.i18n
WARNING: missing resource: verb.max.desc for com.sun.javatest.tool.i18n
WARNING: missing resource: verb.quiet.name for com.sun.javatest.tool.i18n
WARNING: missing resource: verb.quiet.desc for com.sun.javatest.tool.i18n
java.lang.ClassCastException: sun.net.www.protocol.jar.URLJarFile$URLJarFileEntry cannot be cast to java.util.jar.JarFile$JarFileEntry
at java.util.jar.JarFile.verifiableEntry(JarFile.java:900)
at java.util.jar.JarFile.getInputStream(JarFile.java:890)
at sun.net.www.protocol.jar.JarURLConnection.getInputStream(JarURLConnection.java:162)
at java.net.URL.openStream(URL.java:1112)
at com.sun.javatest.tool.ManagerLoader.loadManagers(ManagerLoader.java:79)
at com.sun.javatest.tool.Main.run(Main.java:258)
at com.sun.javatest.tool.Main.main0(Main.java:140)
at com.sun.javatest.tool.Main.main(Main.java:120)
at com.sun.jck.lib.jck4jdk.Main.run(Main.java:619)
at com.sun.jck.lib.jck4jdk.Main.main(Main.java:526)

I'm going to start with this being a build problem(?)