You could also shade/relocate dependency classes within the uber/fat jar. It has pitfalls but it is very easy to set up.
On Thursday, July 7, 2016, Massimilian Mattetti <massi...@il.ibm.com> wrote: > Hi Jim, > > the approach of using namespace from HDFS looks promising. I need to > investigate a little on how it works but I guess I will take your advice. > Thank you. > > Cheers, > Massimiliano > > > > > From: James Hughes <jn...@virginia.edu > <javascript:_e(%7B%7D,'cvml','jn...@virginia.edu');>> > To: user@accumulo.apache.org > <javascript:_e(%7B%7D,'cvml','user@accumulo.apache.org');> > Date: 07/07/2016 08:28 PM > Subject: Re: java.lang.NoClassDefFoundError with fields of custom > Filter > ------------------------------ > > > > Hi Massimiliano, > > I'm a fan of producing uber jars for this kind of thing; we do that for > GeoMesa. There is one gotcha which can come up: if you have several uber > jars in lib/ext, they can collide in rather unexpected ways. > > There are two options to call out: > > First, Accumulo has support for loading jars from HDFS into namespaces. > With that, you could have various namespaces for different versions or > different collections of iterator projects. If you are sharing a dev cloud > with other projects or co-workers working on the same project that can be > helpful since it would avoid restarts, etc. Big thumbs-up for this > approach! > > Second, rather than having an uber jar, you could build up zip files with > the various jars you need for your iterators and unzip them in lib/ext. If > you did that for multiple competing iterator projects, you'd avoid > duplication of code inside uber-jars. Also, you'd be able to see if there > are 8 versions of Log4J and Guava in lib/ext...;) It wouldn't be as > powerful as the namespace, but there's something nice about having a > low-tech approach. > > Others will likely have varied experiences; I'm not sure if there's an > established 'best practice' here. > > Cheers, > > Jim > > On Thu, Jul 7, 2016 at 12:56 PM, Massimilian Mattetti < > *massi...@il.ibm.com* > <javascript:_e(%7B%7D,'cvml','massi...@il.ibm.com');>> wrote: > Thanks for your prompt response, you are right Jim. There is a static > dependency to Log4J in my lexicoder. Adding the Log4J Jar to the classpath > solved the problem. > Would you suggest to use an Uber Jar to avoid this kind of problems? > > Regards, > Massimiliano > > > > > From: James Hughes <*jn...@virginia.edu* > <javascript:_e(%7B%7D,'cvml','jn...@virginia.edu');>> > To: *user@accumulo.apache.org* > <javascript:_e(%7B%7D,'cvml','user@accumulo.apache.org');> > Date: 07/07/2016 06:25 PM > Subject: Re: java.lang.NoClassDefFoundError with fields of custom > Filter > ------------------------------ > > > > > Hi Massimilian, > > As a quick note, your error says that it could not initialize class > accumulo.lexicoders.MyLexicoder. Did you provide all the dependencies for > your class on Accumulo's classpath? > > That exception (or similar) can occur if there is a static block in your > MyLexicoder class which can't run properly. > > Cheers, > > Jim > > > On Thu, Jul 7, 2016 at 11:19 AM, Massimilian Mattetti < > *massi...@il.ibm.com* > <javascript:_e(%7B%7D,'cvml','massi...@il.ibm.com');>> wrote: > Hi, > > I have implemented a custom filter and a custom lexicoder. Both this two > classes are packed in the same jar that has been deployed under the > directory $ACCUMULO_HOME/*lib*/*ext*of my Accumulo servers (version > 1.7.1). The lexicoder is used by the filter to get the real object from the > accumulo value and test some conditions on it. When I tried to scan the > table applying this filter I got the following exception: > > Caused by: java.lang.NoClassDefFoundError: Could not initialize class > accumulo.lexicoders.MyLexicoder > at accumulo.filters.MyFilter.<init>(MyFilter.java:24) > at sun.reflect.GeneratedConstructorAccessor9.newInstance(Unknown > Source) > at > sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) > at java.lang.reflect.Constructor.newInstance(Constructor.java:422) > at java.lang.Class.newInstance(Class.java:442) > at > org.apache.accumulo.core.iterators.IteratorUtil.loadIterators(IteratorUtil.java:261) > at > org.apache.accumulo.core.iterators.IteratorUtil.loadIterators(IteratorUtil.java:237) > at > org.apache.accumulo.core.iterators.IteratorUtil.loadIterators(IteratorUtil.java:218) > at > org.apache.accumulo.core.iterators.IteratorUtil.loadIterators(IteratorUtil.java:205) > at > org.apache.accumulo.tserver.tablet.ScanDataSource.createIterator(ScanDataSource.java:193) > at > org.apache.accumulo.tserver.tablet.ScanDataSource.iterator(ScanDataSource.java:127) > at > org.apache.accumulo.core.iterators.system.SourceSwitchingIterator.seek(SourceSwitchingIterator.java:180) > at > org.apache.accumulo.tserver.tablet.Tablet.nextBatch(Tablet.java:880) > at org.apache.accumulo.tserver.tablet.Scanner.read(Scanner.java:98) > at > org.apache.accumulo.tserver.scan.NextBatchTask.run(NextBatchTask.java:69) > at > org.apache.htrace.wrappers.TraceRunnable.run(TraceRunnable.java:57) > ... 4 more > > > I do not undestand how it is possible that the class loader is able to > find the filter and no the lexicoder. Am I missing something? > > Thanks, > Massimiliano > > > > > > > >
