IntelliJ IDEA 2019.1 Help

Analyze Java Stream operations

Java 8 Streams may sometimes be difficult to read and debug, as to understand how a program reached a certain output, you may need to insert additional breakpoints, and analyze each transformation inside a stream.

IntelliJ IDEA provides a solution to this by letting you visualize what is going on in Java Stream operations

When the debugger stops before or inside a Stream API calls chain, click the Trace Current Stream Chain icon stream debugger icons stream debugger svg in the Debugger toolbar. After the current data stream has been evaluated, you get a visualization of what happens to each element in each transformation, and how its value changes as it passes all steps in a stream:

debug stream trace split view

Click the Flat Mode button to see all operations at once in one view:

debug stream trace flat view
Last modified: 20 June 2019