Unlock Java Performance: How to Use IntelliJ IDEA’s Built‑In Profiler

Previously the author used JProfiler for performance analysis, but now finds IntelliJ IDEA Ultimate’s built‑in Profiler very effective, eliminating the need for JProfiler.

IDEA Profiler also outperforms the free Java JFR Profiler plugin; the screenshot shows the Java JFR Profiler UI built with Firefox Profiler HTML, which offers a poorer experience.

1. Quick Start

To begin profiling in IDEA Ultimate, click the three‑dot icon at the top‑right of the IDE or the Play icon next to a code line, then select Profile with IntelliJ Profiler .

2. CPU and Memory Analysis

The profiler tool window offers several ways to view collected data, such as heat maps, call trees, method lists, timelines, or events.

2.1 Hotspot View

This view visualizes the call stack of selected threads over time; wider stack frames indicate longer execution time, and colored blocks differentiate native, library, and user code.

2.2 Call Tree

This view shows the percentage of CPU time each method consumes, execution paths, and total sample counts, helping quickly overview application activity and spot critical execution paths.

2.3 Method List

This view lists methods recorded during profiling, sorted by cumulative sample time. Selecting a method reveals callers or callees.

2.4 Timeline

The timeline visualizes thread activity over time, aiding detection of abnormal GC events, multithreading issues such as deadlocks, and other anomalies.

2.5 Events

This view displays data related to JVM events, including class loading, garbage collection, and operating‑system events.

3. Real‑Time CPU and Memory Charts

On the Profiler Home screen you can select other Java processes and obtain memory and thread snapshots as well as real‑time CPU and memory usage charts.

Unlike static charts, real‑time data helps visualize resource consumption, identify bottlenecks, and understand how specific events affect program performance.

4. Exporting Results

The IDE automatically saves profiling results as .jfr files for CPU or memory sampling and .hprof files for memory snapshots. These files can be opened later in the IDE or on a server.