[RFC]: Linkage Error fix.

[Deepak Bhole]

* Dr Andrew John Hughes <ahughes at redhat.com> [2011-04-18 13:10]:
> On 09:45 Mon 18 Apr     , Andrew Haley wrote:
> > On 15/04/11 20:55, Deepak Bhole wrote:
> > 
> > > Did you look into how URLCloassLoader and others mitigate the problem?
> > > If I am not mistaken, all class load requests go through JNLPClassLoader,
> > > and synchronizing on each such call can get expensive.
> > 
> > In 1.6 ClassLoader.loadClass() is a synchronized method anyway.
> > 
> > There's something of a myth about the expense of synchronization that
> > isn't usually justified by actual measurements.  It's usually only a
> > compareAndSwap, and there is little pain for uncontended cases.
> > Avoiding synchronization with more complex schemes may actually be
> > slower; you have to measure it.
> > 
> 
> Be correct first.  Only then worry about performance.

Replying here for this message:

http://mail.openjdk.java.net/pipermail/distro-pkg-dev/2011-April/013664.html

The new patch synchronizes all of loadClass. I am against this
approach with the current design. 

The latter part of loadClass() connects to remote sites to download
additional jars. Networks are unreliable and synchronizing a critical
method like loadClass knowing it can get delayed on network is a bad
idea IMO.

That is one of the reasons I suggested studying how URLClassLoader does
it.. it too has to deal with remote connectivity for loading, so it
probably has a cleaner solution for this.

Cheers,
Deepak