java - How do I extend a class? -

i have class: model, many functions, such draw(), rotate() etc.

now have class called cube want able work same way model.

i have in cube class constructor:

model m3d = new model();         m3d.build(obj);

so want able in class call like:

mcube.draw();

and m3d perform draw().

ok. in class call:

class cube extends model {...}

then can do:

cube mcube = new cube();         mcube.build(obj); mcube.draw();

Expalin