Using someone else’s software in you app without obtaining their permission could constitute copyright infringement and end up in you getting sued. Whether your authorized use constitutes copyright infringemnet depends on how much you take and how you use it.
Subject to some important limitations, copyright protects source code (code written in high-level computer languages consisting of English-like words and symbols readable by humans, such as C++, and Java), object code (the series of binary ones and zeros read by the computer itself to execute a program, but not readable by ordinary humans), microcode (instructions that tell a microprocessor chip how to work) and other forms of computer code such as Java byte code.
Copyright protects both applications programs (programs that perform a specific task for the user, such as word processing, will and trust writing, accessing the World Wide Web, bookkeeping or playing a video game) and operating systems and utility programs (programs that manage a computer’s internal functions and facilitate use of applications programs).
Wholesale copying or software piracy takes a variety of forms, including:
Learn more about Copyright and Ownership Rights.
Copying only a small portion of a program’s code could constitute copyright infringement. Then again, it might not. Aparticular routine or subroutine or other piece of code may enjoy little or no copyright protection. In this event, copying it wouldn’t be an infringement. On the other hand, if the code is protected, copying only a small amount could be an infringement, particularly if it is a highly creative or important example of the programmer’s art. Copyright infringement has been found to exist where only 14 lines of source code out of a total of 186,000 lines were copied verbatim. (SAS Inst., Inc. v. S&H Computer Sys., Inc., 605 F.Supp. 816 (M.D.Tenn. 1985).) You’ll usually be better off not copying other people’s code.
Copyright infringement is not limited to the crude wholesale copying described above. It can take a more subtle form—creating “new” software from old, for example, by transferring a chunk of code to the new program and subsequently modifying it. If such a “new” program contains a substantial amount of copyrighted material from an existing program, it may constitute a derivative work. You need to obtain permission to create a derivative work from someone else’s software. Common examples of derivative works include:
Learn when Using Copyrighted Material is Acceptable.