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From: =?ISO-8859-1?Q?Herv=E9?= BOUTEMY <herve.boutemy@free.fr>
To: Maven Developers List <dev@maven.apache.org>
Subject: Re: maven git commit: better plugin/extensions realm parent
 classloader
Date: Sun, 11 Jan 2015 20:48:16 +0100
Message-ID: <2065407.nie9OzZjI5@herve-desktop>
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 <23297958.7W1RTh25cN@herve-desktop> <54B2B085.80406@ifedorenko.com>
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Le dimanche 11 janvier 2015 12:19:01 Igor Fedorenko a =E9crit :
> Opened https://jira.codehaus.org/browse/MNG-5752, thank you for the
> reminder.
thank you: I now better understand the reasoning

>=20
> The change does not affect classloading of "normal" maven runtime, so=

> there is no need to update the diagram or documentation.
IIUC, in the Wiki, what is currently described as "system classloader" =
is now=20
"initial classloader, containing classworlds", which is the system when=
 using=20
CLI but may be another classloader in other situations where Maven is=20=

integrated

> Speaking of
> which, that documentation is somewhat outdated and does not mention c=
ore
> extensions realm, for example. I meant to update it some time ago, bu=
t
> could not find the sources of the diagram. Does anyone know where the=
y are?
if you look at attachements, there is a svg associated with the png ima=
ge

>=20
> I do not believe this change deserves dedicated integration test, at
> least not in maven. There is only so many ways you can access system
> classloader and if anyone decides to change this in the future javado=
c
> comment should give enough context.
ok

Regards,

Herv=E9

>=20
> --
> Regards,
> Igor
>=20
> On 2015-01-11 11:17, Herv=E9 BOUTEMY wrote:
> > please:
> > 1. create a Jira issue
> > 2. update our Class loading documentation [1] with MNG and Maven ve=
rsion
> > reference
> >=20
> > then ideally, having a core IT to show what difference is expected =
from
> > new
> > code would be great (I don't know how hard this one can be)
> >=20
> > Regards,
> >=20
> > Herv=E9
> >=20
> >=20
> > [1]
> > https://cwiki.apache.org/confluence/display/MAVEN/Maven+3.x+Class+L=
oading>=20
> > Le jeudi 8 janvier 2015 13:09:10 ifedorenko@apache.org a =E9crit :
> >> Repository: maven
> >>=20
> >> Updated Branches:
> >>    refs/heads/master 5f71f9789 -> bb4988496
> >>=20
> >> better plugin/extensions realm parent classloader
> >>=20
> >> Signed-off-by: Igor Fedorenko <ifedorenko@apache.org>
> >>=20
> >>=20
> >> Project: http://git-wip-us.apache.org/repos/asf/maven/repo
> >> Commit: http://git-wip-us.apache.org/repos/asf/maven/commit/bb4988=
49
> >> Tree: http://git-wip-us.apache.org/repos/asf/maven/tree/bb498849
> >> Diff: http://git-wip-us.apache.org/repos/asf/maven/diff/bb498849
> >>=20
> >> Branch: refs/heads/master
> >> Commit: bb4988496a0e3b50ee5a1922bcd54f731eb2d5b2
> >> Parents: 5f71f97
> >> Author: Igor Fedorenko <ifedorenko@apache.org>
> >> Authored: Thu Jan 8 08:08:42 2015 -0500
> >> Committer: Igor Fedorenko <ifedorenko@apache.org>
> >> Committed: Thu Jan 8 08:08:47 2015 -0500
> >>=20
> >> ------------------------------------------------------------------=
----
> >>=20
> >>   .../maven/classrealm/DefaultClassRealmManager.java    | 14
> >>   ++++++++++++--
> >>   1 file changed, 12 insertions(+), 2 deletions(-)
> >>=20
> >> ------------------------------------------------------------------=
----
> >>=20
> >>=20
> >> http://git-wip-us.apache.org/repos/asf/maven/blob/bb498849/maven-c=
ore/src
> >> /ma in/java/org/apache/maven/classrealm/DefaultClassRealmManager.j=
ava
> >> ------------------------------------------------------------------=
----
> >> diff
> >> --git
> >> a/maven-core/src/main/java/org/apache/maven/classrealm/DefaultClas=
sRealmM
> >> an
> >> ager.java
> >> b/maven-core/src/main/java/org/apache/maven/classrealm/DefaultClas=
sRealmM
> >> an
> >> ager.java index 3584d53..a5bb352 100644
> >> ---
> >> a/maven-core/src/main/java/org/apache/maven/classrealm/DefaultClas=
sRealmM
> >> an
> >> ager.java +++
> >> b/maven-core/src/main/java/org/apache/maven/classrealm/DefaultClas=
sRealmM
> >> an
> >> ager.java @@ -59,6 +59,16 @@ public class DefaultClassRealmManager=

> >>=20
> >>       implements ClassRealmManager
> >>  =20
> >>   {
> >>=20
> >> +    /**
> >> +     * During normal command line build, ClassWorld is loaded by =
jvm
> >> system classloader, which only includes +     * plexus-classworlds=
 jar
> >> and possibly javaagent classes, see
> >> http://jira.codehaus.org/browse/MNG-4747. +>>=20
> >>      * <p>
> >>=20
> >> +     * Using ClassWorld to determine plugin/extensions realm pare=
nt
> >> classloaders gives m2e and integration test harness +     * flexib=
ility
> >> to
> >> load multiple version of maven into dedicated classloaders without=

> >> assuming
> >> state of jvm system +     * classloader.
> >> +     */
> >> +    private static final ClassLoader PARENT_CLASSLOADER =3D
> >> ClassWorld.class.getClassLoader(); +
> >>=20
> >>       @Requirement
> >>       private Logger logger;
> >>=20
> >> @@ -329,7 +339,7 @@ public class DefaultClassRealmManager
> >>=20
> >>               throw new IllegalArgumentException( "extension plugi=
n
> >>               missing"
> >>=20
> >> ); }
> >>=20
> >> -        ClassLoader parent =3D ClassLoader.getSystemClassLoader()=
;
> >> +        ClassLoader parent =3D PARENT_CLASSLOADER;
> >>=20
> >>           Map<String, ClassLoader> foreignImports =3D
> >>          =20
> >>               Collections.<String, ClassLoader>singletonMap( "",
> >>=20
> >> getMavenApiRealm() ); @@ -347,7 +357,7 @@ public class
> >> DefaultClassRealmManager
> >>=20
> >>           if ( parent =3D=3D null )
> >>           {
> >>=20
> >> -            parent =3D ClassLoader.getSystemClassLoader();
> >> +            parent =3D PARENT_CLASSLOADER;
> >>=20
> >>           }
> >>          =20
> >>           return createRealm( getKey( plugin, false ), RealmType.P=
lugin,
> >>=20
> >> parent, parentImports, foreignImports, artifacts );
> >=20
> > -------------------------------------------------------------------=
--
> > To unsubscribe, e-mail: dev-unsubscribe@maven.apache.org
> > For additional commands, e-mail: dev-help@maven.apache.org
>=20
> ---------------------------------------------------------------------=

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