In the olden days, it was pretty common to make apps that supported two launch modes: 1. entry point in main() created its own window using JFrame or whatever. 2. But also extend Applet so as to run in the browser.
These days, the second mode no longer works because no browser supports applets. But the first mode still works fine. It would STOP working if the applet API were removed. (In particular, class loading would fail if the JVM can't find the parent class.) Normally, when we talk about removing APIs, there is a simple bit of messaging that goes something like this: 1. This is hopefully a simple code change (e.g., stop extending Applet, since it does you no good anyway). 2. If you're not ready to make the code change, stay on an old version for now 3. If you're not going to be ready soon, use an LTS release. There's a cluster of vague implicit assumptions buried in such messaging, such as: 1. The application is actively maintained, or at least there exists a person or group of people nominally in charge of maintaining it. 2. The user and developer of the application are one and the same person, or at least know each other or have some sort of business relationship or SOMETHING. 3. In short, it assumes that if the application doesn't run, the developer has some reason to care. If the developer doesn't care, it's presumably because the app has no users and hence nobody cares. In the case of the applet API, this is all largely false. There are people who once upon a time put a cute little applet on the web, and also made it runnable standalone. If anyone happens to find this useful to them, then all the better, but those people are not customers, just like someone is not your customer just because they happen to read your blog. In other words, if these cute little former applets stop working, the original author has no incentive to care and might not even notice for many years. But even though these are all unmaintained, it does not mean they are unused! They may indeed have users, possibly users who find them indispensable! But those users may not have access to the code, and may not be programmers even if they did have access. To those users, removing the applet API means that these apps no longer work on the latest JDK, and they have no one to complain to. For a while, they can stay on old JDK, but eventually this becomes harder and harder as old JDK versions may not support new operating systems and CPUs and stuff. (Not everyone knows how to set up a VM and an emulator and stuff.) Also, some people may be too nervous to run an old JVM that hasn't gotten security updates in a long time. Conversely, consider the cost of keeping these APIs. They would still be deprecated. Nobody is filing bug reports against them, since they are unusable anyway. They are not "literally free" but the maintenance burden for the OpenJDK team should be only marginally higher than the maintenance burden of dead code. Thoughts? Thanks, Mark.
