Over the past year we worked a lot on the performance of the Spring-related tooling for Eclipse. In this session we present our lessons learned. We show how we identified Eclipse-specific performance bottlenecks, how we solved and/or worked around them, and demo the tools we used for this. We will walk through a number of real cases that we solved and discuss how we solved them. For example, we will discuss how we improved build times of Spring projects by a factor of 10, and reduced memory consumption at the same time. All of the presented cases are not specific to Spring tooling, so that the solutions are directly applicable to other Eclipse plugins. The areas that we will cover include using the JDT API, processing types and type hierarchies in source and class files, accessing resources and file content, scaling some algorithms, and more.