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6.3.3 IBM Classes

IBM’s Eclipse project (which we begin to cover in Chapter 10) provides a large GUI API library called SWT. We won’t go into that here; it is covered in Chapter 17. Of more immediate interest is IBM’s enhanced BigDecimal class (com.ibm.math.BigDecimal) which addresses a lot of deficiencies in Sun’s implementation of decimal arithmetic. We will be using the standard Java class in our book (as it is the same for all development kits we cover), but you might want to take a look at IBM’s FAQ document on their enhanced BigDecimal

class.5 It also appears that IBM’s class may become the official Sun version in Java 5.0 when it comes out. The primary feature of this class is its ability to deal correctly with rounding and precision, which is of great benefit in financial and scientific applications. Check out IBM’s documentation and see if this is something you should use.

Note that Java bytecodes are Java bytecodes. You can download and use the IBM class with the Sun Java Runtime. It is there if you need it.


One thing you will notice right away when you unpack the IBM Java SDK is that it has virtually all of the same commands as does the Sun Java SDK, but there is a whole bunch of them duplicated with a mysterious “_g” suffix. What’s up with that?

These versions run a Java VM that was compiled with debug information, so that you can report information about bugs and errors that is of use to IBM SDK developers in locating and fixing problems. These versions should not be used for production work, but only to recreate and report bugs.


Well, we told you this one would be short. With a handful of minor exceptions, the IBM Java SDK is a complete drop-in replacement for the Sun Java SDK. You could go back to the previous chapter and repeat every example and exer- cise with the IBM Java SDK, and you would get the same results. There is definitely some comfort in knowing that even though you don’t have an Open Source Java VM and SDK, at least you have two vendors the produce function- ally identical development environments. You are not trapped into a single vendor’s offering.


5. http://www2.hursley.ibm.com/decimalj/decfaq.php


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What you still don’t know after reading this chapter is similar to what you still didn’t know after reading Chapter 5. IBM Java SDK has many things we have not covered, including security policy files, JNI, and RMI.


The best source of information about IBM’s Java technology is IBM itself. Search the alphaWorks section of their Web site; we used http:// www.alphaworks.ibm.com/nav/java?openc=java+-+Developer+Kits and found entries for the Java 1.3 Development Kit for Linux, as well as other Java-related downloads, including the Jikes Open Source compiler.