A traditional Java profiler consists of two components. One collects profile data from the running application and the other is a visualization user interface to query the data. The profiler capabilities are limited by the data collected but also by the provided reports and functionality. This can be limiting when it comes to complex query of data. In this session we will introduce mjprof. It is an open source textual visualization profiler. It is extremely powerful as it enables you to compose a sequence of simple steps (monads) such as filters, transformations, group-by which let you slice and dice the data to pinpoint the problem. Working with mjprof resembles working with UNIX pipes. We will explain how to use this tool and present use cases and success stories, using this profiler in the last months. mjprof is written in Java and can be found on github as part of the AdoptOpenJDK project.