Help with open source project customization

Hello, Our company would like to start using one open source project as part of one of our products, but we need to do some customizations first. The project is [login to view URL] We've been able to compile the project using maven following the instructions, but we are not familiar with programming languages and technologies used in this project. The objective of this freelancer project is NOT to do any customization, but to provide the following information: (1) We would like to use Eclipse or Netbeans to import the project and be able to work with it. Your job is to suggest which IDE is more suitable for this project and what plugins and tools are needed to build the project using one of this IDEs. (2) We are particularly interested in customizing the UI subproject. What's the right tool and method to easily test changes to the UI in this project? All selected tools must run on Windows. As the result of this project we expect to receive a detailed document with instructions and information to points (1) and (2). Thank you.