Is it good practice to use assert in Java?

in my algortihms lectures, my lecturer always maintained the usefulness of assertions. theyre mostly used for test and debugging purposes, which my be why u do see code using it. but yes, theyre highly recomended. they can be disabled if you're worried abt performance. normally i use System.out.println or breakpoints to test, but assertions are one way too. here's what i mean:

For example, to prove that sort+reverse is equivalent to sort in reverse order:
Method 1: sort(int[] arr, int len)
// pre: len is the length of the array arr
// post: arr is sorted in ascending order
Method 2: reverse(int[] arr)
// post: the order of elements in arr is
// reversed (e.g. [9 5 10] -> [10 5 9])
Assertion 1: the length of arr is len
sort(arr,len);
Assertion 2: arr is sorted in ascending order
reverse(arr);
Assertion 3: the order of arr is reversed