If you have been working in AEM for a while now, you are probably aware of the tools we used to have like CRXDE, CRXDE-lite, VLT. With the latest release of AEM 6.x, Adobe has released this Eclipse plugin that can be used moving forward. This page here, provides information as to how you can start off your new project development using these tools. However, if you are working on an existing project on a previous version of AEM (say 5.x), then you need to refer to another set of instruction guide here. This instruction guide talks about a “Getting Started in 5 minutes” as to how to create a new project and then import into Eclipse. If you are already on an existing project you may not need, but if you are a maven buff and want to start off by working with a maven archetype then this guide will fail for a specific step. I realized that this guide is incomplete and some key steps are missing to make this work.
If you are interested in using Eclipse for working on JSPs instead of CRXDE, them the step you will be most interested will be How to work with JSPs. For your JSPs to work you will need to add dependencies for TagLibs to compile and this guide provides a list of dependencies which you need to add. That list is not exhaustive and project the content bundle project will not compile. When working on this guide, you have to use the dependencies from this gist.
This is a key step, and unless you get all those dependencies and if your project is brand new your project will not compile. If you are using an existing project it may just work if you have added those dependencies, but from experience as we dont compile JSPs those dependencies will not kick in. The code still works on CQ server because those dependencies are available at runtime.