And what's wrong with: ClassLoader cl = Clazz.class.getClassLoader();
On Thu, Mar 20, 2014 at 11:03 AM, haosdent <[email protected]> wrote: > > should prefer the Class's CL because the client's application affects the > TCCL. > You could call "Thread.currentThread().setContextClassLoader(classLoader)" > before the classloader load "Configuration" or "HbaseObjectWritable" class. > > You consider the logic below should be better: > ClassLoader cl = Clazz.class.getClassLoader(); > if (cl == null) { > cl = Thread.currentThread().getContextClassLoader(); > } > > But variable "cl" couln't be null here. So the code snippet above is > equivalent to the following code: > > ClassLoader cl = Clazz.class.getClassLoader(); > > > On Thu, Mar 20, 2014 at 4:39 PM, Amit Sela <[email protected]> wrote: > > > I understand the benefits of TCCL, but I think, and I would like to hear > > the "why not", that code that may run in the client side (like in the > case > > of Configuration and HbaseObjectWritable examples I gave) should prefer > the > > Class's CL because the client's application affects the TCCL. > > > > > > On Thu, Mar 20, 2014 at 8:56 AM, haosdent <[email protected]> wrote: > > > > > Because we could change the value of "Thread.currentThread(). > > > getContextClassLoader()" by > > "Thread.currentThread().setContextClassLoader( > > > classLoader)". But we couldn't change the value of > > > "this.getClass().getClassLoader()". > > > Maybe a little confused, TCCL is more flexible than the class's CL. > > > > > > > > > On Thu, Mar 20, 2014 at 2:43 PM, Amit Sela <[email protected]> > wrote: > > > > > > > I understand that. But why ? Why prefer the TCCL over the class's CL > ? > > > > On Mar 20, 2014 3:00 AM, "haosdent" <[email protected]> wrote: > > > > > > > > > Sometimes we would use > "Thread.currentThread().setContextClassLoader( > > > > > classLoader);" to specify classloader. So > > > > > "Thread.currentThread().getContextClassLoader();" > > > > > should be the first choice. > > > > > > > > > > > > > > > On Thu, Mar 20, 2014 at 1:53 AM, Amit Sela <[email protected]> > > > wrote: > > > > > > > > > > > Hi all, > > > > > > I'm running with Hadoop 1.0.4 and HBase 0.94.12 bundled (OSGi) > > > > versions I > > > > > > built. > > > > > > Most issues I encountered are related to class loaders. > > > > > > > > > > > > One of the patterns I noticed in both projects is: > > > > > > > > > > > > ClassLoader cl = > > Thread.currentThread().getContextClassLoader(); > > > > > > if(cl == null) { > > > > > > cl = Clazz.class.getClassLoader(); > > > > > > } > > > > > > > > > > > > Where Clazz is the Class containing this code. > > > > > > > > > > > > I was wondering about this choice... Why not go the other way > > around: > > > > > > > > > > > > ClassLoader cl = Clazz.class.getClassLoader(); > > > > > > if(cl == null) { > > > > > > cl = Thread.currentThread().getContextClassLoader(); > > > > > > } > > > > > > > > > > > > And in a more general note, why not always use Configuration (and > > let > > > > > it's > > > > > > cl be this.getClass().getClassLoader()) to load classes ? > > > > > > > > > > > > That would surely help in integration with modularity frameworks. > > > > > > > > > > > > Thanks, > > > > > > Amit. > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > Best Regards, > > > > > Haosdent Huang > > > > > > > > > > > > > > > > > > > > > -- > > > Best Regards, > > > Haosdent Huang > > > > > > > > > -- > Best Regards, > Haosdent Huang >
