The FileSystem API of Java 7 allows to read and add entries from or to a Zip file using the Java NIO file API in the same way as operating on any other filesystem.
The FileSystem is a resource that should be properly closed after use, therefore the try-with-resources block should be used.
Path pathToZip = Paths.get("path/to/file.zip");
try(FileSystem zipFs = FileSystems.newFileSystem(pathToZip, null)) {
Path root = zipFs.getPath("/");
... //access the content of the zip file same as ordinary files
} catch(IOException ex) {
ex.printStackTrace();
}Map<String, String> env = new HashMap<>();
env.put("create", "true"); //required for creating a new zip file
env.put("encoding", "UTF-8"); //optional: default is UTF-8
URI uri = URI.create("jar:file:/path/to/file.zip");
try (FileSystem zipfs = FileSystems.newFileSystem(uri, env)) {
Path newFile = zipFs.getPath("/newFile.txt");
//writing to file
Files.write(newFile, "Hello world".getBytes());
} catch(IOException ex) {
ex.printStackTrace();
}