Java fails to start when classes.tar is not loaded via the vfs tar plugin

Sebastian Sumpf Sebastian.Sumpf at
Thu Nov 21 10:53:52 CET 2019

Hello Pirmin,

On 11/20/19 5:33 PM, Duss Pirmin wrote:
> Hello Genodians
> I'm tying to optimize the startup time of a java application (ARM
> board), as starting the JVM takes several seconds on our board.
> To do this, I tried to move the classes.tar in to a separate vfs
> component [1]. This crashes the JVM with the following error message:
> [init -> java] Error occurred during initialization of VM
> [init -> java] java.lang.NoClassDefFoundError:
> java/util/concurrent/ConcurrentHashMap
> [init -> java] 	at
> java.lang.WeakPairMap.<init>(java.base/
> [init -> java] 	at java.lang.Module.<clinit>(java.base/
> Can anyone tell me, why this happens?
> Is there a way to fix this?
> [1]

I have tried to reproduce your issue by applying your commit and testing
it on base-hw in Qemu (pbxa9). This worked so far. The
'NoClassDefFoundError' usually occurs if something goes wrong during
class compilation or dependency loading, or something is corrupt. If
Java could not find a class it would throw a 'ClassNotFoundException'.



Sebastian Sumpf
Genode Labs ·

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

More information about the users mailing list