Jul 19, 2012

Maven parallel build

Hi All,

I have looked for a while for this option, wondered how could it be that they don't have it.

Finally i found it, since maven 3v, they add an experimental option, the T option.

You can now run maven build parallel way. Meaning, maven will check which parts from the project tree he can build in parallel and do it.

Performance ?

Big boost, something like >20%, Do it for your self and compare, you want regret it.

Good also for CI (Jenkins for example)


First way,
"mvn -T 4 clean install"

-T   => Stands for telling maven to use the parallel way.

4    => Means, 4 threads to use.

Second way and my preferred,
"mvn -T 4C clean install"

-T   => Stands for telling maven to use the parallel way.

4C  => Means, 4 threads on each core


Jul 17, 2012

logback asyncappender

Since 1.0.4 logback has the famous async appender we all waited for at least me.
It's great news, not to use any custom appenders or custom async appender but their in house.

Just to inform you.

Jul 12, 2012

CDH4 Hadoop Ubuntu precise server

I got this error "JAVA_HOME "
When trying to install CDH4 of Cloudera Hadoop standalone version.
Although i did all the needed configuration + echo $JAVA_HOME is fine.
+ writing "java" works + writing "java -version" works ok .
Nothing really helped except
1. go to /etc/hadoop/conf
2. edit hadoop-env.sh
add export JAVA_HOME=/usr/lib/jvm/jdk1.6.0_32
then try again, i was trying to format the namenode.

Hoped it helped.

Jul 9, 2012


YARN is the up coming version 2.0.0 which is now in alpha and MRV2 as for map reduce version 2.0
They used to call mrv2 for the previous 0.23 version.

More about it can be found in cloudera site.

Spring Hibernate Envers java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.(I)V

Issue occurred to my college at work. It means that spring uses already the envers as a dependency inside it and you are trying to add it also with a different version. As result -> Conflict.
For me it happened with
spring 3.0.5
hibernate 3.6.0.FINAL
* We added hibernate-envers 3.6.0.FINAL.

Replacing hibernate-envers with the latest, current latest is 4.1.4 but you should look in maven repository.