Windows monitoring software for Solr recommendation

[TK Solr]

My client's Solr 6.6 running on a Windows server is mysteriously crashing 
without any JVM crash log. No unusual activities recorded in solr.log. GC log 
does not indicate the OOM situation. It's a simple single-core, single node 
deployment (no solrCloud). It has very light load. No indexing activities were 
running near the crash time.

After exhausting all possibilities (suggestions are welcome), I'd like to 
recommend to install some monitoring software but I couldn't find one that works 
on Windows for a Java based software. (Some I found can monitor only EXEs. Since 
all java software shares the same EXE, java.EXE, those won't work.) Can anyone 
recommend some? They don't need to be free but can't be very expensive since 
it's a very lightly used Solr system. Perhaps less than $500?

TK