Is it possible to run a legacy Java application on Android? The application has been built with Java 1.3. According to my research I need to convert the class files to the corresponding dex files using a tool like dx. What level of support should I expect from dx tool? Do you think I will face many incompatibility issues? Keep in mind that I don't have control to the source code of the application but if necessary I could ask for it. The legacy software is proprietary. Thanks in advance.
In short: no, because it's probably not an Android application.
The Java 1.3 classes themselves should work, for the most part, without major issues, but any user interface elements, main entry points, and so forth will have to be replaced with Android equivalents.
You might be able to salvage data objects and business logic, however, if your existing classes have a clear delineation between these and the user interface.