The size and position of any given frame is unpredictable unless
you specify it. Specifying the size is easy. Just call the frame's
setSize() method like this
f.setSize(150,150);
This size does not include the title bar so you'll need to account
for that separately. To determine the height of a
Frame's title bar call its insets() method and
look at the top member of the resulting
java.awt.Insets object. That will be the height of the title
bar. That is,
int titleBarHeight = f.insets().top;
Moving the Frame to the proper place on the screen
takes a little more effort. You move a Frame with the
setLocation(int x, int y) method. However x and y are
relative to the screen, not to the applet.
When a window is first created, it's invisible. Add components
to the Frame while it's still invisible. The effect of
buttons, labels and other widgets popping onto a layout in rapid
succession while the window jumps around and changes size can be
quite disconcerting. When you're done adding components, resizing
and moving the Frame, make it visible by calling its
setVisible() method like so:
f.setVisible(true);
You can resize a frame to the exact size necessary for what it holds using the pack() method:
f.pack()