Closing an anonymous stream in method call

Question

Will an anonymous stream in a method call be closed in the same manner an anonymous stream that is created in an object instantiation will be?
I know this will close the anonymous FileInputStream:
DataInputStream in =
new DataInputStream(new FileInputStream("filename.txt"));
/* ... code ... */
in.close();But will this?
MyPropertiesClass myPropertiesClass = new MyPropertiesClass();
myPropertiesClass.store(new FileOutputStream("file.txt"));MyPropertiesClass extends Properties, and uses its store().
I know the JavaDoc for Properties says:
"After the entries have been written, the output stream is flushed. The output stream remains open after this method returns."
My question is will the FileOutputStream("file.txt") be closed and garbage collected eventually after this method call because I don't have a reference to it? myPropertiesClass sticks around for a long time afterwards, will the FileOutputStream as well?
Thanks for any insight,
KJ

Answer 1

My question is will the FileOutputStream("file.txt") be closed and garbage collected eventually after this method call because I don't have a reference to it? > myPropertiesClass sticks around for a long time afterwards, will the FileOutputStream as well?Your only hope would be if FileOutputStream overrode finalize and closed the stream there -- but it doesn't (check the API -- finalize isn't overridden). I doubt if Properties retains a reference to the OutputStream you pass to store -- why would it need to? In any case, the bottom line is that output stream isn't being closed until your process exits.
Why not bite the bullet and rewrite that line of code so that you can explicitly close the stream?
OutputStream out = new FileOutputStream("file.txt");
try {
    myPropertiesClass.store(out);
} finally {
    out.close();
}It's not one line, but who cares? You could wrap it up in a short utility method:
static void storeProperties(Properties properties, String path) {...}