Hi Liang, Thank you for your response! The provided guidelines are quite helpful. I have noticed that different packages in JDK use the assert keyword to varying degrees. I wonder if this is more a matter of developer preference (if it is not the performance reason mentioned by Alan). :P
Regards, Daohan ________________________________ From: liangchenb...@gmail.com <liangchenb...@gmail.com> Sent: Sunday, July 16, 2023 7:09 To: Daohan Qu <quadh...@outlook.com> Cc: core-libs-dev@openjdk.org <core-libs-dev@openjdk.org> Subject: Re: Questions about using `assert` in Java Hi Daohan, assert keyword is safely usable within production code. I don't think it has a significant performance impact if it is not enabled. Thus, you should not enable it in production unless you are debugging. A package that uses assert extensively is java.lang.invoke package. For me, these are the general notes for using assert: 1. They should not perform side-effects, such as changing variables. Having -ea, -esa and no flag run differently is definitely not desirable. 2. assert should not be used to defend against incorrect user inputs; it should only be used to ensure the correctness of internal states of your program, as assert is optional. Chen Liang On Sun, Jul 16, 2023 at 12:54 AM Daohan Qu <quadh...@outlook.com<mailto:quadh...@outlook.com>> wrote: Dear developers, I'm a graduate student doing software engineering research. Recently, I came across some interesting facts about Java assert statements and have a few questions to ask. Although the assert keyword has been around for a long time and is handy for invariant checks, it does not seem to be widely used. For example, in the famous j.u.c packages, nearly all assert statements are commented out [1]. My questions are, should assert be heavily used in Java programs, especially in production code? And should we enable them in the production code? By the way, I have read a useful article about using assertions in Java [2], but it does not provide clear answers to my questions above. Thank you in advance! [1] https://github.com/search?q=repo%3Aopenjdk%2Fjdk+assert+path%3A%2F%5Esrc%5C%2Fjava.base%5C%2Fshare%5C%2Fclasses%5C%2Fjava%5C%2Futil%5C%2Fconcurrent%5C%2F%2F&type=code [2] https://docs.oracle.com/javase/8/docs/technotes/guides/language/assert.html Regards, Daohan Qu
