The following test hung in the 2017-07-07 JDK10-hs nightly:

com/sun/jdi/RedefineClasses.sh

Here is a snippet of the .jtr file:

----------System.out:(27/1343)----------
--Compiling first version of /cygdrive/c/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808/shtest.java with options:
compiling shtest.java

--Starting jdb, address=kkkk.29808
--Starting debuggee with args from TESTVMOPTS and/or TESTJAVAOPTS: -Xmixed -server -XX:MaxRAMFraction=8
Listening at address: kkkk.29808
Cmd: c:/users/aurora/CommonData/TEST_JAVA_HOME/bin/java -classpath C:/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808 -DHANGINGJAVA-29808_DEB -XX:-ShowMessageBoxOnError -Xmixed -server -XX:MaxRAMFraction=8 -Djtreg.classDir=C:/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808 -showversion -agentlib:jdwp=transport=dt_shmem,address=kkkk.29808,server=n,suspend=y shtest
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
Initializing jdb ...
>
VM Started: No frames on the current call stack

main[1] Deferring breakpoint shtest:26.
It will be set after the class is loaded.
main[1] > Set deferred breakpoint shtest:26
in a4
i + j = 3335
out from a4
def

Breakpoint hit: "thread=main", shtest.a3(), line=26 bci=0
26 System.out.println("out from a3"); // @1 breakpoint

main[1] main[1] main[1] main[1] out from a3
out from aa
Timeout signalled after 2,880 seconds
----------System.err:(12/797)----------
ShellScaffold.sh: Running with timeout_factor = 16
--Sending cmd: stop at shtest:26
--Sending cmd: run
java version "10-internal"
Java(TM) SE Runtime Environment (fastdebug build 10-internal+0-2017-07-07-164630.iggy.8183991)
Java HotSpot(TM) Server VM (fastdebug build 10-internal+0-2017-07-07-164630.iggy.8183991, mixed mode, emulated-client)
--Sending cmd: redefine shtest C:/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808/shtest.class
--Sending cmd: redefine shtest C:/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808/shtest.class
--Sending cmd: redefine shtest C:/Users/aurora/sandbox/results/workDir/classes/1/com/sun/jdi/aa29808/shtest.class
--Finish execution with sending "quit" command to JDB
--Sending cmd: quit
--Quit cmd was sent

The test machine is:

Intel Xeon 2893 MHz, 2 cores, 15G, Win32 / Windows Server 2012 R2 Standard,

so it is not wimpy. Based on the output the test was running
and making progress. The test timed out at 48 minutes.