Your suggestion for cut and paste programming is part and parcel to what the Java library is all about.
That said, it takes a great deal of understanding to make the interfaces correct and bullet proof. This is very advanced stuff, and while I support people taking elementary programming (to understand how computers work, and to see if you enjoy this option), the idea of cutting and pasting programs will not work without pretty much understanding all the pieces.
"Cut and Paste" is one of the professional secrets of the masters in this trade. You make new programs quickly by using bits and pieces of old programs that worked in a similar context.
As you mentioned, this takes a lot of skill and knowledge of multiple techniques to do it correctly. An untrained, unskilled person is not going to be able to do it.