object type

hi,

can clarify in point form.

1)object type itself is a abap program or only methods/events that attached to it are abap program?

2) in swo3, i simply click 1 object type, and click the program button, i can see the abap program. so i wonder object type itself is a program.

3) may i know where to key in the program. the editor seems a bit different. not in se80 or se38?

4) where to find all the possible object-type. for example, BUSxxx, idocxxx, TVxxx, etc

thanks