I am in the process of helping develop a commercial Java program. We want to use a certain third-party LookAndFeel in the GUI. The problem is that the LookAndFeel library is GPL licensed. Since we are planning to sell our product, would it be legal to use that GPL LookAndFeel in our product?
The LookAndFeel in question is the InfoNode Look And Feel
If you're willing to abide by the terms of the GPL, then yes it's legal.
But chances are if you're selling a commercial app, releasing the source to any Tom, Dick and Harry who buys a copy is a non-starter. If you're not willing to release your source code to anyone who uses it, no you can't license the library under the GPL.
However, the particular library you're interested in is dual-licensed. If the GPL doesn't suit you, you can instead license the library under the InfoNode Software License.
Basically, the developers of the library are using the standard practice of releasing the library under the GPL for open-source developers to use, and effectively requiring commercial developers to pay for the library if they want to use it in a commercial application.
Keep in mind that the GPL has many faces. Depending on the type of GPL license you're using, the rules may be vastly different.
The GPL is known as an infectious license, meaning that any proprietary code that uses GPL code becomes blanketed by the GPL license. This means that, if you did sell your product, you would also need to include the entire source code. The people you sell the product to can modify it, copy it, give it away for free, etc.
If you do sell it, you may be able to profit by offering support that, as the original authors, you are in a better position to do than those who have obtained it and are distributing it themselves.
If the license is LGPL, then as long as the library is only used and is not tightly coupled into the application, then the main body of the proprietary codebase can remain licensed under a proprietary license. However, you still must include the source of the library when you distribute your product, just not your main codebase.
DISCLAIMER: I am not a lawyer. This is my interpretation of the two licenses. It is best to seek advice from a professional specializing in law.
