Apart from the core editor and debugger components provided by IDEA, most of the additional functionalities are available by using plugins. IDEA is modular in its nature. We already talked a lot about plugins in the previous chapters. If you want to write in a language other than Java, you need the corresponding plugins. If you require the IDE to support the framework of your choice, be it Spring or Vaadin, you need the plugin as well. The JetBrains team made a lot of additional plugins available in their repository. There are also a lot of plugins available from independent vendors; you can browse through them in Settings. The list of plugins is growing constantly. However, if you find it insufficient, let's say you want to incorporate some custom tool your company uses, IDEA provides a well-documented API helpful to develop your own extension. We will focus on writing one in this chapter. The whole plugin API is huge and it's surely out of the scope of...