`$` does mean end of input in Java, unless you explicitly ask for multiline mode. In the latter case it means `(?=$|\n)` if also in Unix-lines mode, and the horrible `(?=$|(?<!\r)\n|[\r\u0085\u2028\u2029])` otherwise.

I wrote a compiler from Java regex to JavaScript RegExp, in which you'll find that particular compilation scheme [1].

Edit: also quoting from [2]:

> By default, the regular expressions ^ and $ ignore line terminators and only match at the beginning and the end, respectively, of the entire input sequence. If MULTILINE mode is activated then ^ matches at the beginning of input and after any line terminator except at the end of input. When in MULTILINE mode $ matches just before a line terminator or the end of the input sequence.

[1] https://github.com/scala-js/scala-js/blob/eb160f1ef113794999...

[2] https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pa...