Aspose.Words for Java supports the current java version (jdk 1.6) and two preceding versions: jdk 1.5 and jdk 1.4. Jdk 1.3 does not supported by Aspose.Words for Java. And such a support is not planned at all. There are two main reasons:
1. Jdk 1.3 has too much difference in API with the following jdk 1.4 so we can’t easily translate ours code base to jdk 1.3.
2. Jdk 1.3 has too little user base. For example, this is only second question about jdk 1.3 for four years.
So I’m sorry, but it’s will be better for you to upgrade to more modern jdkL