resource leak when using numbered split zip file

[IcyBiscuit]

Hi,

We use this library to extract zip files on a Linux server (about 6000 files per day). After running a few days, the OS reports a too many open files error.

I use lsof -p PID to list open files and found about 40000 zip files are opened by one process.

After analysing the code, this issue may caused by an unclosed RandomAccessFile in net.lingala.zip4j.io.inputstream.NumberedSplitRandomAccessFile#randomAccessFile

here is the sample code to reproduce the issue:

@Test
public void numberSplitFd() throws IOException {
  String name = "/path/to/random-files/random.out copy %d.zip.001";
  for (int i = 1; i <= 10; i++) {
    // open the file, and close it using try-with-resource
    try (RandomAccessFile raf = new NumberedSplitRandomAccessFile(String.format(name, i),
        RandomAccessFileMode.READ.getValue())) {
    }
  }
  // add a breakpoint here and use lsof to check opened files
}

test files:
random-files.zip

lsof -p PID | grep 'zip.001'

java    8912 icybiscuit   11r   REG   1,4   1178   31937242 /Users/icybiscuit/Downloads/random-files/random.out copy 1.zip.001
java    8912 icybiscuit   12r   REG   1,4   1178   31937243 /Users/icybiscuit/Downloads/random-files/random.out copy 2.zip.001
java    8912 icybiscuit   13r   REG   1,4   1178   31937255 /Users/icybiscuit/Downloads/random-files/random.out copy 3.zip.001
java    8912 icybiscuit   14r   REG   1,4   1178   31937256 /Users/icybiscuit/Downloads/random-files/random.out copy 4.zip.001
java    8912 icybiscuit   15r   REG   1,4   1178   31937257 /Users/icybiscuit/Downloads/random-files/random.out copy 5.zip.001
java    8912 icybiscuit   16r   REG   1,4   1178   31937258 /Users/icybiscuit/Downloads/random-files/random.out copy 6.zip.001
java    8912 icybiscuit   17r   REG   1,4   1178   31937259 /Users/icybiscuit/Downloads/random-files/random.out copy 7.zip.001
java    8912 icybiscuit   18r   REG   1,4   1178   31937260 /Users/icybiscuit/Downloads/random-files/random.out copy 8.zip.001
java    8912 icybiscuit   19r   REG   1,4   1178   31937261 /Users/icybiscuit/Downloads/random-files/random.out copy 9.zip.001
java    8912 icybiscuit   20r   REG   1,4   1178   31937268 /Users/icybiscuit/Downloads/random-files/random.out copy 10.zip.001

add an override close method can resolve this issue

// net.lingala.zip4j.io.inputstream.NumberedSplitRandomAccessFile#close
@Override
public void close() throws IOException {
  if (null != randomAccessFile) {
    randomAccessFile.close();
  }
  super.close();
}

[srikanth-lingala]

Thanks for the detailed bug report. I appreciate that. I added the close method to NumberedSplitRandomAccessFile. Considering the urgency of this bug, I will make a (minor) release today after the build goes through.

[srikanth-lingala]

Fixed in v2.11.0 released today