FlowTracker is a Java agent that tracks data flow through Java programs in real-time. By monitoring how a program reads, manipulates, and writes data, FlowTracker provides valuable insights, such as connecting inputs and outputs to understand where data originates from. A demonstration using the Spring PetClinic application showcases how FlowTracker can track HTTP responses, Thymeleaf templates, and even trace data back to its source in the database. Although still a proof of concept, FlowTracker is a powerful tool for understanding program behavior, with certain limitations in performance and tracking capabilities. The internals of how FlowTracker works involve instrumenting code, dataflow analysis, and tracking origins of both I/O and code-derived data.
https://github.com/coekie/flowtracker