A five word horror story: Your code suddenly stops working. It may have worked just fine when it was written ten years ago, but now it's suddenly failing on JDK 13 or JDK 14 early access builds. We will discuss how to figure out whether that's because of a JDK issue, a configuration issue, or some aspect of the code itself. Then we'll dive into how to go about fixing it, based on experiences from the OpenJDK Quality Outreach.
From the simplicity of badly cross compiled code, to the surprising side effects of locale date updates, through OpenJDK Quality Outreach we get to see our and other code fail in interesting ways. We'll cover some common traps and pitfalls, and their fixes.