The modularization of the Java SE Platform in JDK 9 will bring many benefits, but also many changes. Existing code that uses only official Java SE Platform APIs and supported JDK-specific APIs should continue to work without change. Code that uses certain deprecated features, however, or any JDK-internal APIs, is likely to break. This session will show you how to prepare existing libraries and applications for JDK 9, and how to get old code working on JDK 9 even when you can't update it.