A JProfiler developer utilizes the JProfiler tool, a Java profiler, to analyze and optimize Java applications. They evaluate performance bottlenecks, memory leaks, multi-threading problems, and resolve them to enhance application efficiency. The developer uses JProfiler's extensive features, such as CPU profiling, memory profiling, thread profiling, and VM telemetry for detailed diagnostics. They also monitor the application's live behavior, scrutinize heap dumps, and track memory usage. Furthermore, with JProfiler, they measure execution times, analyze database calls, and inspect the call tree to improve code execution. They continuously monitor, troubleshoot, and optimize the application to ensure its smooth and efficient performance.