How to hide cursor in a Swing application?

It appears that the Cursor class does not have a "blank" cursor to begin with, so one could define a new "blank" cursor using the Toolkit.createCustomCursor method.

Here's one way I've tried which seems to work:

// Transparent 16 x 16 pixel cursor image.
BufferedImage cursorImg = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB);

// Create a new blank cursor.
Cursor blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
    cursorImg, new Point(0, 0), "blank cursor");

// Set the blank cursor to the JFrame.
mainJFrame.getContentPane().setCursor(blankCursor);

Edit

Regarding the comment about everything inside the JFrame ending up without a cursor, it seems that the Components which are contained in the JFrame will end up inheriting the cursor of the container (the JFrame), so if it is a requirement to have a certain Component have the cursor appear, one would have to manually set the desired cursor.

For example, if there is a JPanel contained in the JFrame, then one could set the cursor of that JPanel to the system's default using the Cursor.getDefaultCursor method:

JPanel p = ...
// Sets the JPanel's cursor to the system default.
p.setCursor(Cursor.getDefaultCursor());

tl;dr AWT Toolkits are still bugged in 2017'; the proper solution is thus to call

  w.setCursor( w.getToolkit().createCustomCursor(
                   new BufferedImage( 1, 1, BufferedImage.TYPE_INT_ARGB ),
                   new Point(),
                   null ) );

instead.

As per Javadoc page for createCustomCursor,

Creates a new custom cursor object. If the image to display is invalid, the cursor will be hidden (made completely transparent), and the hotspot will be set to (0, 0).

It would follow from that that

w.setCursor( w.getToolkit().createCustomCursor( null, null, null ) );

should do the trick. Sadly, there is a bug related to this case NOT handled by the code, see e.g. http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7150089 (this particular is for MacOS, but by browsing the source you may easily find that there's no checking for 1st param Image value validity in any of the Toolkit platform implementations; there's tracker.isErrorAny() checking, which doesn't do it's job in this case), so passing null or invalid Image simply throws a NPEx.

When using the LWJGL under Mac OS you need to do this:

System.setProperty("apple.awt.fullscreenhidecursor","true");