Re: [Jamvm-general] Starting JamVM with OpenJDK rt.jar

[Frieder B. <ber...@go...>]

The installation guide for JamVM states, that you need a normal openJDK
build, in which you replace the libjvm.so with the one produced by the
JamVM build.
This way, one uses the starting executable of the openJDK and not the one
of JamVM.

If you use GNU classpath, the starting executable of JamVM is used.
I would like to do the same while using the java *.class files of openJDK.
I was able to get the classloading started (using a simple HelloWorld), but
it stops somewhere after loading java/security/Guard (list of the classes
that are loaded is provided below)
I always get a segfault in src/thread.c in getExecEnv (): threadSelf
returns a null pointer even though it has some valid value before.

The same libjvm.so used inside openJDK runs fine, but for the project I am
working on, JamVM should be the starting point.

With rt.jar I meant the standard Java classes, that are provided by openJDK.

I'm confused why the null pointer occurs and if it is possible what I try
to do.


Classname loaded: java/lang/ClassLoader
Classname loaded: java/lang/Class
Classname loaded: java/io/Serializable
Classname loaded: java/lang/Object
Classname loaded: java/lang/reflect/GenericDeclaration
Classname loaded: java/lang/reflect/AnnotatedElement
Classname loaded: java/lang/reflect/Type
Classname loaded: java/lang/String
Classname loaded: java/lang/Comparable
Classname loaded: java/lang/CharSequence
Classname loaded: java/lang/Cloneable
Classname loaded: java/lang/StackTraceElement
Classname loaded: java/lang/Throwable
Classname loaded: java/lang/BootstrapMethodError
Classname loaded: java/lang/LinkageError
Classname loaded: java/lang/Error
Classname loaded: java/lang/InternalError
Classname loaded: java/lang/VirtualMachineError
Classname loaded: java/lang/ClassFormatError
Classname loaded: java/lang/NoSuchFieldError
Classname loaded: java/lang/IncompatibleClassChangeError
Classname loaded: java/lang/OutOfMemoryError
Classname loaded: java/lang/NoSuchMethodError
Classname loaded: java/lang/InstantiationError
Classname loaded: java/lang/IllegalAccessError
Classname loaded: java/lang/ClassCastException
Classname loaded: java/lang/RuntimeException
Classname loaded: java/lang/Exception
Classname loaded: java/lang/StackOverflowError
Classname loaded: java/lang/ArithmeticException
Classname loaded: java/lang/AbstractMethodError
Classname loaded: java/lang/ArrayStoreException
Classname loaded: java/lang/NullPointerException
Classname loaded: java/lang/NoClassDefFoundError
Classname loaded: java/lang/UnsatisfiedLinkError
Classname loaded: java/lang/InterruptedException
Classname loaded: java/lang/InstantiationException
Classname loaded: java/lang/ReflectiveOperationException
Classname loaded: java/lang/ClassNotFoundException
Classname loaded: java/lang/IllegalAccessException
Classname loaded: java/lang/IllegalArgumentException
Classname loaded: java/lang/NegativeArraySizeException
Classname loaded: java/lang/IllegalThreadStateException
Classname loaded: java/lang/IllegalMonitorStateException
Classname loaded: java/lang/ArrayIndexOutOfBoundsException
Classname loaded: java/lang/IndexOutOfBoundsException
Classname loaded: java/lang/StringIndexOutOfBoundsException
Classname loaded: sun/reflect/UnsafeStaticFieldAccessorImpl
Classname loaded: sun/reflect/UnsafeFieldAccessorImpl
Classname loaded: sun/reflect/FieldAccessorImpl
Classname loaded: sun/reflect/FieldAccessor
Classname loaded: sun/reflect/MagicAccessorImpl
Classname loaded: sun/reflect/ConstantPool
Classname loaded: java/security/PrivilegedActionException
Classname loaded: sun/reflect/MethodAccessorImpl
Classname loaded: sun/reflect/MethodAccessor
Classname loaded: sun/reflect/ConstructorAccessorImpl
Classname loaded: sun/reflect/ConstructorAccessor
Classname loaded: java/nio/Buffer
Classname loaded: java/nio/DirectByteBuffer
Classname loaded: sun/nio/ch/DirectBuffer
Classname loaded: java/nio/MappedByteBuffer
Classname loaded: java/nio/ByteBuffer
Classname loaded: java/io/ObjectStreamField
Classname loaded: java/lang/Thread
Classname loaded: java/lang/Runnable
Classname loaded: java/lang/ThreadGroup
Classname loaded: java/lang/Thread$UncaughtExceptionHandler
Classname loaded: java/lang/System
Classname loaded: java/lang/RuntimePermission
Classname loaded: java/security/BasicPermission
Classname loaded: java/security/Permission
Classname loaded: java/security/Guard

2016-04-28 18:07 GMT+02:00 Andrew Hughes <gnu...@re...>:

> ----- Original Message -----
> > Hey Guys,
> >
> > the Readme for JamVM describes two ways to use it, one with Gnuclasslib
> and
> > one with openJDK.
> >
> > Even so, is it possible to start the JamVM executable and tell it where
> the
> > *.class-files of the openJDK are to reduce the overhead of IcedTea?
> > I tried it, but only get the following message on the terminal:
> > Exception occurred while VM initialising.
> > java/lang/NoClassDefFoundError: java/lang/ClassLoader
> >
> > Any help would be appreciated!
> >
> > Frieder
> >
> >
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> > https://lists.sourceforge.net/lists/listinfo/jamvm-general
> >
>
> What "overhead"? IcedTea just builds JamVM and the class library, both
> of which you need for a complete JDK. What rt.jar are you trying to use
> with it?
> --
> Andrew :)
>
> Senior Free Java Software Engineer
> Red Hat, Inc. (http://www.redhat.com)
>
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>
>