2 replies to this topic

[gregwarner]

When I'm done writing to an OutputStream, I always call close() to free up those resources. My question is, when nesting several OutputStream's inside wrapper classes, when you close the outermost object, does Java go through the nested classes and close them as well? In other words, is it okay to do this:

ObjectOutputStream oos = new ObjectOutputStream(new GZIPOutputStream(new FileOutputStream(output_file_name)));

oos.writeObject(some_serializable_object);

oos.close();

// Program goes on to do more stuff.

My question is, has the innermost FileOutputStream been closed? Or are those file resources still active at this point?

or is it more proper to do this:

FileOutputStream fos = new FileOutputStream(output_file_name);

GZIPOutputStream gzos = new GZIPOutputStream(fos);

ObjectOutputStream oos = new ObjectOutputStream(gzos);


oos.writeObject(some_serializable_object);


oos.close();

gzos.close();

fos.close();


// Program goes on to do more stuff.

[ZekeDragon]

close() automatically closes all inner streams, this allows you to make chained streams with temporary objects.
Citation

[gregwarner]

Thanks for the tip.