There is too much controversy of moving from Ant to Maven, but maybe people don’t know that ant build scripts can be used with maven.

These are the step by step instructions:

1. Create a minimal project.xml, that we’ll call POM (Project Object Model) or project descriptor. The most tedious task will be adding the dependencies needed to compile your classes, but you can use this search tool to get groupId and artifactId for them. If any of that dependencies are not at ibiblio repository copy the url of the repo, you’ll need it later. Change sourceDirectory to suit your needs.

   
   
       3
       yourgroup
       yourjar
       
           
           
               hibernate
               hibernate
               2.1.6
           
           
               springframework
               spring-core
               1.1
           
           
       
       
           src/java
       
   
   

2. Create a file maven.xml. This is the place to write ant scripts. You just have to rename targets to goals. You can get the current dir using ${basedir}.

   <?xml version="1.0" encoding="ISO-8859-1"?>
   <project
     xmlns:j="jelly:core"
     xmlns:ant="jelly:ant"
     xmlns:maven="jelly:maven"
     xmlns:util="jelly:util">
     <goal name="doSomething">
       <!-- do some stuff using ant scripts -->
       <delete dir="${basedir}/adir"/>
       <mkdir dir="${basedir}/adir" />
       <copy todir="${basedir}/adir">
         <fileset dir="${basedir}/anotherdir"/>
       </copy>
     </goal>
   </project>
   

3. If you use some dependency not at ibiblio create a project.properties file with a line maven.repo.remote=http://www.ibiblio.org/maven,http://cvs.apache.org/repository where http://cvs.apache.org/repository is the url you copied early. You can add as much urls as you want, separated by commas.
4. Now you can run maven doSomething to execute the ant goal, and you can also call maven java:compile to compile the classes, maven site to generate a good looking website,…
5. A common complain of Ant users is speed. You can call maven doSomething java:compile to run both goals or use maven console, where ypu can type any goal without the startup penalty time.
6. Now you should be ready to check maven reference docs to explore the lots of features that maven can offer.

To sum up you can do with Maven everything you can do with Ant and many more things, so why don’t give it a try?

J2SE 5 (Tiger) has been finally released as General Availability.
Download it
Check the new features and enhancements
Tiger Roars: The Release of Java 2 Platform, Standard Edition (J2SE) 5.0, an Interview with Sun Fellow Graham Hamilton

The Apache Software Foundation, the most respected organization in the open source world, has opened a mailing list to allow posting job offers to the members of the community. Offers can be sent the to jobs (at) apache (dot) org.

Some configuration is shared across many projects and duplication must be avoided, e.g. for hibernate configuration this can be achieved using ArrayList for properties of type List and a custom class HibernateProperties for properties of type Properties.

    
        
            
        
        
            
        
        
            
        
    

    
        
            
                ${hibernate.dialect}
                ${hibernate.show_sql}
                ${hibernate.hbm2ddl.auto}
            
        
    

    
        
            
                net/sf/oness/party/model/party/bo/Party.hbm.xml
            
        
    

This way mappingResources can be overriden in each project for their set of classes and hibernateProperties can also be overriden to get values from JNDI as I do in the ONess project.

As Rick Hightower stated in a previous comment, another way to avoid running out of memory is forking the virtual machine. When doing so the MAVEN_OPTS doesn’t affect the new vm, you have to use the maven.junit.jvmargs property.

maven.junit.fork=true
maven.junit.jvmargs=-Xmx256m

If you are getting out of memory errors when running Maven you can increase the amount of memory used.
You only need to set the environment variable MAVEN_OPTS, e.g. MAVEN_OPTS=-Xmx512m if you want to use 512 MB of memory.

Dion wrote an interesting entry about the joining of JDO and EJB. A new spec is being created to provide an unified persistence API for both standard and enterprise java editions using POJOs.