Computer Sc. E books for non Computer Sc. students

Often, technical students of non Computer Sc. branches need to have a knowledge about some computer oriented subjects in one or two semesters.Why should they buy those books which they will possibly never require in future.I provide links to those books, for those who do not need to have a physical book...
Here is The Complete Reference to Java, 5th edition, with J2SE 1.4 covered.
http://rapidshare.com/files/277301994/The_Complete_Reference_for_JAVA_---_Herbert_Schildt.pdf
Less than 12 MB, I believe satisfactory resolution.