order of argument in both junit and hamcrest

I saw the following code snippet online

As it mentioned, the argument order of Junit(expected, actual) and Hamcrest(actual, expected) is reversed.

I was wondering what is the reason behind it? Does the argument order really matter for Junit or Hamcrest? If someone accidently placed the argument in the wrong order, will it affect the result? Thanks in advance for any suggestions or help!