* lisp/progmodes/compile.el (compilation-error-regexp-alist-alist):
'javac': Column numbers are 1-based by default; remove subtraction and
η-reduce. Translate regexp to rx (mechanised).
* test/lisp/progmodes/compile-tests.el (compile-tests--test-regexps-data):
Adapt 'javac' test cases to the change.