I created a java application and want to add Apache Commons Codec to it. What is right/legal way to use Apache (or any external library)? Would I be allowed to combine my Apache Commons lib and my project in single .jar, or I have to keep them separate? Where I need to mention about the licence. And the main question is it free? Can I publish my application including Apache Commons.
What is the normal practice using external libraries? I tried to read licence agreement (https://www.apache.org/licenses/LICENSE-2.0), but it didn't give me clear understanding.