Using Intellij IDEA with current JDK

Andrew Haley aph at
Thu Jan 18 17:59:58 UTC 2018

On 17/01/18 17:47, David Lloyd wrote:
> What I've done is to force no JDK at all.  It does present an ugly
> banner[1] at the top but otherwise it seems to work fine - or did,
> until the latest update[2].  If you've already set up a SDK, I think
> there's no way to unset it, so you have to close IDEA, edit your
> xxx.ipr or .idea/modules.xml (I think) and delete the line which
> defines the SDK.

OK, I see.  It works, kinda-sorta, but navigation is pretty useless,
and everything is covered with red squiggles.

> [1] See also:
> [2] The error I see at present is of the type "Package 'java.lang' is
> in the unnamed module, but module 'jdk.compiler' does not read it".
> Previously I had excluded from all source roots, but
> the latest update somehow determines that everything are Java 9
> modules anyway.  I had done this for two reasons: firstly, there are
> not module descriptors in every place where there are sources (for
> example, having a separate "java.base:share" and "java.base:unix" IDEA
> module causes problems because :share has a but :unix
> does not), and secondly, IDEA does not cope well with situations where
> there is more than one (for example if one is
> generated from the other) or if it is simply generated to begin with.
> Sigh.

OK, I'm starting to understand some of the problems.  Thanks.

Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <>
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