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https://issues.apache.org/jira/browse/NETBEANS-63?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16173161#comment-16173161
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Peter Hansson commented on NETBEANS-63:
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99,99% of network tasks may well start before GUI is initialized. Only some
network tasks will invoke the Authenticator (it only gets invoked if there's a
need for it and if the JRE cannot on its own obtain the required credentials
for endpoint/proxy). So there's really no point in asking all network tasks to
wait for GUI. Also this would require that you knew which tasks were performing
network operations. And remember we have to cater for headless applications too.
As a side note: Network tasks on startup are from my experience common in
Platform applications and they are for sure 'legal' operations both in module
installers and in WarmUp tasks. The IDE itself also use the concept namely for
AutoUpdate against NB Update Center. This gets spawned very early (it is in a
module installer, so it is akin to @OnStartup) but we are in luck that this
task does invokeWhenUIReady() and this may be the reason why there hasn't been
many bug tickets as a result of the incorrect order.
> Incorrect startup order
> -----------------------
>
> Key: NETBEANS-63
> URL: https://issues.apache.org/jira/browse/NETBEANS-63
> Project: NetBeans
> Issue Type: Bug
> Components: platform - Module System
> Affects Versions: 8.2, 9.0
> Environment: All
> Reporter: Peter Hansson
> Attachments: NBStartup.pdf
>
>
> As part of analyzing the [freeze bug on
> startup|https://issues.apache.org/jira/browse/NETBEANS-58], I've come across
> something I see as a problem in NB startup sequence.
> Basically I see this sequence in the Platform's main startup thread:
> # @OnStart tasks from modules are spawned
> # ProxySelector is registered
> # WarmUp tasks are spawned
> # Authenticator is registered
> So clearly, tasks that may perform network operations are started _before_
> network infrastructure ({{ProxySelector}} and {{Authenticator}}) has been
> initialized. In real-life it will be hit and miss which comes first.
> I've attached my analysis of the startup sequence as a PDF (in case anyone
> disagrees).
> My idea for a fix is along these lines:
> * I want to continue to allow @Startup tasks and WarmUp tasks to be launched
> early (as today), but a task must itself be aware if it needs network or UI
> initialization or whatever.
> * I want to create a new {{RunLevel}}. Currently the RunLevel feature is
> under-used in my experience. There's really only one RunLevel at the moment,
> namely the {{GuiRunLevel}} which is always executed last. (despite the name
> it applies both to GUI and headless scenario). So I would add an additional
> RunLevel, {{NetworkRunLevel}}, where network infra will be initialized. The
> new RunLevel will run before GuiRunLevel. This mimics what operating systems
> does and I believe this was also the original idea of the RunLevel feature.
> * Currently RunLevels are found by Lookup so that anyone can install their
> own RunLevel. I don't think this feature is used (it probably requires to be
> Friend), but it is nice and we should of course still cater for it.
> * Create a public interface where a task can wait for a given RunLevel to
> have executed. I'm thinking some kind of annotation or something.
> * Existing WarmUp tasks will need to be amended to clearly indicate at what
> RunLevel they can execute. (default will be that all RunLevels have
> executed). Module tasks (@OnStartup) will also need to be catered for.
> Ideas, comments, please. There may be simpler ways of solving the problem but
> we should really keep an eye on allowing to start tasks as early as we allow
> today (i.e. not make startup performance worse).
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