On 25/01/2019 11:06 pm, yumin qi wrote:
Hi, David
I am confused here.
As you pointed out:
Java anonymous classes are not VM anonymous classes.
VM anonymous classes are created by Unsafe_DefineAnonymousClass only.
Is my understanding right? All all lambda classes are vm anonymous?
I don't know if it is correct to say "all lambda classes" as I don't
know the full translation strategy for lambda expressions, but yes some
lambda generated classes are VM anonymous classes.
David
Thanks
Yumin
On Fri, Jan 25, 2019 at 7:18 PM David Holmes <david.hol...@oracle.com
<mailto:david.hol...@oracle.com>> wrote:
<dropped jdk-dev>
On 25/01/2019 6:52 pm, yumin qi wrote:
> Hi,
>
> I have a question of anonymous class. We know the anonymous
class with a
> host_klass, and the flag is set when the InstanceKlass is created
after the
> class parsed. In case of a regular java class file, the flag will
be set
> correctly but for the case it is not set:
> SystemDictionary::parse_stream or resolve_from_stream, which
is called
> from JVM_DefineClassWithSource or jni_defineClass. The stack
trace like:
>
> #1 0x00007f1127291ce7 in
> SystemDictionary::resolve_from_stream(class_name=0x7f0ee40243f0,
> class_loader=..., protection_domain=...,d__=0x7f0f04001000) at
>
/home/ws/openjdk/8/jdk8u/hotspot/src/share/vm/classfile/systemDictionaryShared.cpp:656
> #1 0x00007f1127291ce7 in SystemDictionary::resolve_from_stream
> (class_name=0x7f0ee40243f0, class_loader=..., protection_doma
> in=...,
> st=0x7f0f0a5f3850, verify=true, __the_thread__=0x7f0f04001000)
> at
>
/home/ws/openjdk/8/jdk8u/hotspot/src/share/vm/classfile/systemDictionary.cpp:1234
> #2 0x00007f1126f3cadb in jvm_define_class_common
(env=0x7f0f04001220,
> name=0x7f0f0a5f3e60 "com/google/common/collect/Iterato
> rs$3",
> loader=0x7f0f0a5f3f20, buf=0x7f0ee401e210
"\312\376\272\276", len=943,
> pd=0x7f0f0a5f3f48,
> source=0x7f0f0a5f3a60
"jar:file:/home/<...>/lib/guava-19.0.jar!/",
> verify=1 '\001', __the_thread__=0x7f0f04001000) at
>
/home/yumin.qi/ws/openjdk/8/jdk8u/hotspot/src/share/vm/prims/jvm.cpp:1082
> #3 0x00007f1126f3d019 in JVM_DefineClassWithSource
(env=0x7f0f04001220,
> name=0x7f0f0a5f3e60 "com/google/common/collect/Itera
> tors$3",
> loader=0x7f0f0a5f3f20, buf=0x7f0ee401e210
"\312\376\272\276", len=943,
> pd=0x7f0f0a5f3f48,
> source=0x7f0f0a5f3a60
"jar:file:/home/<...>/lib/guava-19.0.jar!/") at
> /home/ws/openjdk/8/jdk8u/hotspot/src/share/vm/prim/jvm.cpp:1102
> #4 0x00007f112581214f in Java_java_lang_ClassLoader_defineClass1 ()
> from
>
/home/ws/openjdk/8/jdk8u/build/linux-x86_64-normal-server-slowdebug/images/j2sdk-image/jre/lib/amd64/libjava.so
> #5 0x00007f11118f5402 in ?? ()
> #6 0x00007f0f0a5f3f48 in ?? ()
> #7 0x00007f0f0a5f3f70 in ?? ()
> #8 0x0000000755dbbc28 in ?? ()
>
> The class name is com.google.common.collect.Iterators$3, and it is an
> anonymous class.
I'm confused. Are you talking about Java level anonymous classes or VM
anonymous classes as created by Unsafe.defineAnonymousClass? Only VM
anonymous classes have a "host class". Java level "anonymous classes"
are just regular classes.
David
-----
> This is an example using Guava. I also can reproduce with jdk13.
>
> The field after parsing:
>
> _nonstatic_oop_map_size = 1,
> _is_marked_dependent = false,
> _has_unloaded_dependent = false,
> _misc_flags = 38, ////// <------------ not set for anonymous
> _minor_version = 0,
> _major_version = 50,
> _init_thread = 0x0,
> _vtable_len = 8,
> _itable_len = 8,
>
> This path is from a custom loader defining a anonymous class,
does not
> set anonymous correctly for the flag. Is this a bug? If in java land,
> supply a host as parameter, it can be set correctly in VM part.
Should I
> file a bug for it?
>
> Thanks
> Yumin
>
