A switch expression is a preview language feature (JEP 12). This essentially means that, even though it is complete, it has a possibility of not being confirmed as a permanent feature in a future Java release. This happens for a reason.

Java runs on billions of devices and is used by millions of developers. The risks are high for any mistake in a new Java language feature. Before permanently adding a language feature to Java, the architects of Java evaluate what the developers have to say about it—that is, how good or bad it is. Depending on the feedback, a preview language feature might be refined before it's added to Java SE or dropped completely. So, if you have any feedback on switch expressions, please share it with amber-dev (https://mail.openjdk.java.net/mailman/listinfo/amber-dev).