Worked on the apache/commons-io repository to refine the semantics of the PeekableInputStream.peek() method, ensuring it provides exact-match, non-consuming peeks into input streams. Focused on correctness by implementing logic that allows users to inspect upcoming data without altering the stream’s state, addressing a key requirement for non-destructive peeking. Enhanced reliability by developing targeted unit tests that validate both the exact-match and non-consuming behaviors, thereby increasing test coverage for input/output stream utilities. Collaborated with another contributor to integrate these changes with related IO-855 work, leveraging Java and unit testing skills to improve code quality and regression protection for users.