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.
This feature is only available for project files. You cannot use Java Stream Debugger to debug libraries or decompiled code.
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
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:
Click the Flat Mode button to see all operations at once in one view:
