imageplus update

stack = new ImageStack( 300, 300 );
stack.addSlice( new FloatProcessor( 300, 300 ) );
imp = new ImagePlus( "", stack );
for ( int i = 0; i < 10; ++i )
{
    stack.addSlice( new FloatProcessor( 300, 300 ) );
    if ( i == 0 )
    {
    imp.show();
    }
    imp.setPosition( imp.getZ() + 1 );
    imp.updateAndDraw();
    Thread.sleep( 1000 );
}