KITFORMA · EDITORIAL ANSWER
Why does repeatedly reading Files.lines eventually exhaust open file handles?
KitForma editorial guide. A lazily read stream may still own an open file. Completing a terminal operation does not replace the resource owner’s close obligation.
Step-by-step answer
A lazily read stream may still own an open file. Completing a terminal operation does not replace the resource owner’s close obligation.
Keep traversal inside try-with-resources:
try (var lines = Files.lines(path, StandardCharsets.UTF_8)) { return lines.filter(this::accept).count(); }. Do not return that stream from a method whose try block already closed it. If returning a lazy stream is necessary, document that the caller must close it.
Run repeated reads of a small fixture and confirm another process can replace or remove the file after each completed operation where the platform permits it. This addresses resource lifetime; it does not bound memory if the pipeline later collects an enormous file into a list.Sources and verification
Sources checked:
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