Users must choose between debugger HCR and application monitor HCR without assistance from tool

[scottkurz]

A small application may wish to use the default <applicationMonitor> config (polling for updates) in which case a "Hot Code Replace" (HCR)-like experience can be achieved even during a regular (non-Debug) "Start".

OTOH, for a larger app that takes longer (30, 60s, whatever) to restart, this is so slow that the only way to achieve an "HCR" experience will be to rely on the Eclipse Debugger HCR support. In this case the applicationMonitor updateTrigger will need to be set to disabled (or mbean).

So you really can't easily switch between Start or Debug and get HCR in both.

In WDT/LDT this issue was solved by having WDT use the mbean as a trigger....but it would avoid issuing the update notification if you were in Debug mode, letting the faster Debugger HCR do its thing.

This config would look like:
<applicationMonitor dropinsEnabled="false" updateTrigger="mbean" />
and IIUC, was generated as a configDropin by WDT.

NOTE

One caveat, note debugger HCR has limitations, e.g you can't add change/add method signatures.

[troy-bishop]

We spoke about this on Slack but I wanted to mention it here so it doesn't get lost. This may or may not be related, but it might also be good to consider how WDT creates the debug launch configuration, rather than always treating it as a 'Remote Java application':

https://github.com/OpenLiberty/open-liberty-tools/blob/1b3dee79881f390b06c3b7a098d710891dbafacf/dev/com.ibm.ws.st.core/src/com/ibm/ws/st/core/internal/launch/BaseLibertyLaunchConfiguration.java#L243

[scottkurz]

No advancement since updating the discussion in the LMP issue here: OpenLiberty/ci.maven#1710 (comment) In the near term some kind of doc, even informal like a Wiki, would be useful.