Yup! I hate this issue. It also happens with json libs if you have an old hadoop !!!
Its really easy also to dump the exact class path at runtime using the ((URLClassLoader)ClassLoader.getSystemClassLoader()).getURLs(); trick... very very very very useful :) I always do this just to make sure before going and mucking with the classpath args. I've found using this trick can save a lot of headaches, especially if your dealing with jars that you can't programmatically get version #'s out of. On Wed, Oct 3, 2012 at 7:45 AM, Ben Rycroft <brycrof...@gmail.com> wrote: > > Hi guys, > > Thanks the speedy replies. > > I will try Harsh's suggestion and see if this solves the issue, if not I will just do what Michael suggested and replace the jars on each of the nodes. > > Thanks again! > > > On Wed, Oct 3, 2012 at 12:39 PM, Harsh J <ha...@cloudera.com> wrote: >> >> Hi Ben, >> >> As long as the switch of libraries doesn't impact the execution of the >> Child task code itself, for Apache Hadoop 1.x, using the config >> "mapreduce.user.classpath.first" set to true may solve your trouble. >> >> On Wed, Oct 3, 2012 at 4:51 PM, Ben Rycroft <brycrof...@gmail.com> wrote: >> > Hi all, >> > >> > I have a jar that uses the Hadoop API to launch various remote mapreduce >> > jobs (ie, im not using the command-line to initiate the job). The service >> > jar that executes the various jobs is built with maven's >> > "jar-with-dependencies". >> > >> > My jobs all run fine except one that uses commons-codec 1.7, I get: >> > >> > FATAL org.apache.hadoop.mapred.Child: Error running child : >> > java.lang.NoSuchMethodError: >> > org.apache.commons.codec.binary.Base64.encodeAsString([B)Ljava/lang/String; >> > >> > I think this is because my jar is including commons-codec 1.7 whereas my >> > Hadoop install's lib has commons-codec 1.4 ... >> > >> > Is their any way to instruct Hadoop to use the distributed commons-codec 1.7 >> > (I assume this is distributed as a job dependency) rather than the >> > commons-codec 1.4 in the hadoop 1.0.3 core lib? >> > >> > Removing commons-codec-1.4.jar from my Hadoop library folder did seem to >> > solve the problem for a bit, but is not working on another VM. Replacing the >> > 1.4 jar with the 1.7 does seem to fix the problem but this doesn't seem too >> > sane. Hopefully there is a better alternative. >> > >> > Thanks! >> >> >> >> -- >> Harsh J > > -- Jay Vyas MMSB/UCHC
