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Prevent file descriptor leak and modernize BufferedWriter creation

pixee:java/prevent-filewriter-leak-with-nio

ImportanceReview GuidanceRequires Scanning Tool
MEDIUMMerge Without ReviewNo

This change prevents a file descriptor leak and modernizes the file writing API pattern.

The way the code is written now, the FileWriter never gets closed. Thus, it is up to the garbage collector's objection finalization process to close them at some point. This is not a good practice, and it can lead to a file descriptor leak. In hot code paths, it could cause exhaustion of all the available file descriptors for the system and lead to denial-of-service conditions.

Our changes look something like this:

-  BufferedWriter writer = new BufferedWriter(new FileWriter(f));
+ BufferedWriter writer = Files.newBufferedWriter(f.toPath());

References