extract from TiledLayer
javadoc page:
Rendering a TiledLayer
A TiledLayer can be rendered by manually calling its paint method; it can also
be rendered automatically using a LayerManager object.
The paint method will attempt to render the entire TiledLayer subject to the clip
region of the Graphics object; the upper left corner of the TiledLayer is rendered
at its current (x,y) position relative to the Graphics object's origin. The rendered
region may be controlled by setting the clip region of the Graphics object
accordingly.
and check this link
http://www.javaworld.com/javaworld/jw-08-2004/jw-0809-j2me-p5.html