Count the words in Java
Java interview exercise on Streams & lambdas, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write wordCounts(text) that counts each word of text, case-insensitively: split on anything that is not a letter, drop empty pieces, lower-case, and collect with groupingBy + counting into a Map<String, Long>.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.