Problems with non Oracle boot JDKs and class file version 52

[Mandy Chung]

On 12/7/12 4:42 AM, Erik Joelsson wrote:
> On 2012-12-07 13:06, David Holmes wrote:
>>
>> Here's the failing command (edited for presentation):
>>
>> /usr/lib/jvm/java-7-openjdk-amd64/bin/java -Xms64M -Xmx1100M
>> -XX:PermSize=32m -XX:MaxPermSize=160m -XX:ThreadStackSize=1536 \
>>
>> -Xbootclasspath/a:/java/embedded/users/dh198349/build-infra/builds/b00/se-linux-i586-ea/jdk/classes 
>>
>>

^^^^ - this seems the cause of the problem?

To run the bootstrap javac (v51), it can't set -Xbootclasspath to 
jdk8/classes (v52).

Mandy

>>
>> "-Xbootclasspath/p:/java/embedded/users/dh198349/build-infra/builds/b00/se-linux-i586-ea/langtools/dist/bootstrap/lib/javac.jar" 
>>
>> -jar
>> /java/embedded/users/dh198349/build-infra/builds/b00/se-linux-i586-ea/langtools/dist/bootstrap/lib/javac.jar 
>>
>> \
>>             -XDprocess.packages -proc:only \
>>             -processor com.sun.tools.javac.sym.CreateSymbols \
>>
>> -Acom.sun.tools.javac.sym.Jar=/java/embedded/users/dh198349/build-infra/builds/b00/se-linux-i586-ea/images/lib/rt.jar 
>>
>> \
>>
>> -Acom.sun.tools.javac.sym.Dest=/java/embedded/users/dh198349/build-infra/builds/b00/se-linux-i586-ea/images/symbols/META-INF/sym/rt.jar 
>>
>> \
>>             java.applet java.awt java.awt.color java.awt.datatransfer
>> java.awt.dnd java.awt.event java.awt.font java.awt.geom java.awt.im
>> java.awt.im.spi java.awt.image java.awt.image.renderable
>> java.awt.print java.beans java.beans.beancontext java.io java.lang
>> ...
>> com.sun.servicetag com.oracle.net com.oracle.nio
>> Error occurred during initialization of VM
>> java/lang/UnsupportedClassVersionError: sun/misc/PostVMInitHook :
>> Unsupported major.minor version 52.0
>>
>> ----
>>
>> Now PostVMInitHook is a class from the closed/Oracle repo. So here is
>> what I think is happening - this closed class gets referenced but
>> because we are on an OpenJDK build it is not found in rt.jar, but is
>> found in our freshly built jdk/classes - hence the jdk7 VM tries to
>> load a JDK 8 class and fails.
>>
>> So it would seem that an OpenJDK VM can not be used to bootstrap the
>> Oracle JDK.
>>
>> Not sure there is anything we can do about that except "don't do that".
>>
>> David
>> -----
>>
> That's what I was suspecting, that open boot cannot bootstrap Oracle 
> JDK. Interesting that we get that far before it falls apart. This 
> looks like it's the generation of symbol files for ct.sym. I tried to 
> reproduce this by building an openjdk only image myself and then using 
> it as boot for a closed build, but that didn't fail.
>
> Configure should try to detect if the bootjdk is unlikely to work at 
> least.
>
> /Erik
>>>
>>> /Erik
>>>
>>> On 2012-12-07 00:35, David Holmes wrote:
>>>> I've now seen two people encounter problems trying to build Profiles
>>>> using the new build system, when their boot JDK is the locally
>>>> installed IcedTea openjdk distribution (7 in one case and 6 in
>>>> another).
>>>>
>>>> The error occurs creating jar files eg
>>>>
>>>> Creating resources.jar
>>>> Error occurred during initialization of VM
>>>> java/lang/UnsupportedClassVersionError: sun/misc/PostVMInitHook :
>>>> Unsupported major.minor version 52.0
>>>>
>>>> Are we using bootclasspath tricks that only work on Oracle JDK?
>>>>
>>>> David
>>>>
>