FileOutputStream try-with-resources doesn't close file descriptor

Question

I have code that extracts some specific large (about 15k entries) binary serialized file archive to folder on disk.

public void extractExact(Path absolutePath, DoubleConsumer progressConsumer) throws IOException
{
    ...
    // Extract to file channel
    try (final FileOutputStream fos = new FileOutputStream(absolutePath.toFile()))
    {
        PakExtractor.Extract(pakFile, Entry, fos.getChannel(), progressConsumer);
    }
 }

extractExact function calls for every entry in archive.

after this, if I try to call Files.delete(<archive_file_path>) method - I will get an exception:

java.nio.file.FileSystemException: The process cannot access the file because it is being used by another process.

I checked my archive file in Process Explorer search and it says that I have ~15k file openings by my java.exe (as many as the files in the archive)

this happens only in windows (jdk1.8.0_162). On Linux I don't have any problems with "zombie" opened files.

Answer 1

Finally - we found the solution. Many thanks to @Netherwire. FileChannel class have map method that does some implicit copy operations with file descriptors, so be careful when use it. Here is more information.