Hi, I'm in Ray Marsh's camp. I know nothing about CORBA and want to write a Java/CORBA application as a learning excercise. I am not clear about when and where CORBA is used. Here at Kenyon college we use three relational databases (Oracle, Sybase, MS SQL Server), and an old VMS-based system called called Poise. How might CORBA enable a link between these tools? What can CORBA do that, for example, JDBC can not? To learn CORBA, do I need access to VisiBroker or other similar tool, or does the 1.2 JDK by itself contain the necessary functionality? Also, what are the best books, WebPages, or tutorials on CORBA or CORBA/Java? Any perspectives are much appreciated. Thanks in advance. Ben Weaver
CORBA and JDBC serve different purposes. JDBC allows a Java class to access a database. CORBA allows a Java class to interact with another program in any one of many different programming languages. You might be better of starting with RMI since the rmiregistry is included in the JSDK. If you understand the RMI concepts you will be much closer to understanding the CORBA concepts. Start with this little puzzle: write a Java class that uses RMI to run a method in another class which uses JDBC to access a database. Do that and you have a multi-tier reusable architecture!
I'm with Tom - I found RMI (designed as a Java-to-Java system) very straightforward to learn, and it's a good way to pick up a lot of distributed computing concepts that are also used in CORBA. If you do want to go on and learn CORBA, you could try and do the same exercise Tom suggested, this time accessing the remote method using CORBA. I used the very basic Java IDL ORB provided in the Java 2 SDK to practice (the relevant packages all start with org.omg.). You might also like to try using RMI-IIOP, which allows RMI applications to communicate with remote CORBA objects using the CORBA network protocol - this gives you the benefits of using CORBA (it doesn't matter what language the remote object is written in) while being almost as simple to write as plain old RMI. The necessary compiler and API are included in the 1.3 version of Java 2, and there's a good tutorial on converting your RMI apps to RMI/IIOP on the Sun site (I think).
Joined: May 10, 2000
Lucy and Tom, Thanks again for the hints! They will enable me to break the ice on CORBA and RMI. Actually, you both killed two birds with one stone, since I had also wanted to know more about the relationship between RMI and CORBA. Ben Weaver