Closing a ByteArrayOutputStream has no effect?

Question

What does this statement, \"Closing a ByteArrayOutputStream has no effect\" (http://java.sun.com/javase/6/docs/api/java/io/ByteArrayOutputStream.html#close()) m

Answer 1

Does ByteArrayOutputStream.close() really release the memory?

No. It does absolutely nothing. You can look at its source code:

public void close() throws IOException {
}

To release the memory, make sure there are no references to it and let the Garbage Collector do its thing. Just like with any other normal object.

File- and Socket-based streams are special because they use non-memory OS resources (file handles) that you can run out of independantly of memory. That's why closing them explicitly is important. But this does not apply to the purely memory-based ByteArrayOutputStream.