FULL PRODUCT VERSION :
java version "1.7.0_02"
Java(TM) SE Runtime Environment (build 1.7.0_02-b13)
Java HotSpot(TM) Client VM (build 22.0-b10, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Versione 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Writing a zip file using the ZipFileSystemProvider causes a memory leak; manipulating big zip files can lead to an OutOfMemoryError.

The test case shows that creating a new zip file and adding many files to it will lead to memory usage constantly growing; the memory will not be released even after the try-with-resources block is exited, closing the zip file.

Using the old ZipOutputStream/ZipEntry interface does not exhibit this behaviour.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.IOException;
import java.net.URI;
import java.nio.file.DirectoryStream;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;


public class ZipLeak {

public static void main(String[] args) throws IOException {
Path origPath = FileSystems.getDefault().getPath("dirWithManyFiles");
Path zipFile1 = FileSystems.getDefault().getPath("newZipFile");
long javaMemory = 0;
try (DirectoryStream<Path> dirStream = Files.newDirectoryStream(origPath);
FileSystem zipFS = createZipFileSystem(zipFile1, true)) {
Path zipRoot = zipFS.getPath("/");
for (Path path : dirStream) {
Files.copy(path, zipRoot.resolve(path.getFileName().toString()));
// print the used memory only after a garbage collection
long newJavaMemory = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
if (newJavaMemory < javaMemory) {
System.out.println(newJavaMemory);
}
javaMemory = newJavaMemory;
}
}
Runtime.getRuntime().gc();
System.out.println(javaMemory);

}

private static FileSystem createZipFileSystem(Path path, boolean create) throws IOException {
final URI uri = URI.create("jar:file:" + path.toUri().getPath());

final Map<String, String> env = new HashMap<>();
if (create) {
env.put("create", "true");
}
return FileSystems.newFileSystem(uri, env);

}
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Do not use zipfs; use ZipOutputStream