If user's stack size resource limit is set to unlimited, as in:

% ulimit -s
unlimited

Then the ecl command (and possibly other HPCC programs) that try to load/initialize the plugin libjavaembed.so will fail with an error:

Invalid thread stack size: -Xss18446744073709551615
The specified size exceeds the maximum representable size.
module initialization 1:4096 threw exception
hqlcollect.cpp(362) : Trying to load dll : javaembed: Unable to initialize JVM (-6)

We can check for this and put a maximum size on the stack limit value passed to the jvm -Xss option.