Using IntelliJ IDEA Diagrams to Visualize Servlet Inheritance and Interface Implementation

When I finally had some free time, I revisited the servlet topic and used IntelliJ IDEA's diagram feature to get a clear visual of the inheritance chain and interface implementations, which I now share.

1. Viewing the Inheritance Chain as a Diagram

Right‑click on the class tab, choose Diagrams , and select either Show Diagram (embedded) or Show Diagram... (floating window).

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Alternatively, you can right‑click the class in the project tree and select Diagrams for the same result.

The resulting diagram for a custom servlet looks like the image below.

The diagram uses blue solid arrows to indicate inheritance and green dashed arrows to indicate interface implementation.

2. Optimizing the Diagram

2.1 Remove Unwanted Classes

If the diagram shows classes you don't care about (e.g., Object or Serializable ), select them and press the Delete key. The cleaned‑up diagram is shown in the following image.

2.2 Show Detailed Class Information

To view fields, methods, constructors, etc., right‑click the diagram and choose Show Categories , or use the toolbar button. You can also filter by visibility level (e.g., show only protected and above).

2.3 Zoom In

Press Alt to activate a magnifier for a closer look at the diagram.

2.4 Add Other Classes to the Diagram

Right‑click and select Add Class to Diagram , then type the class name. The added class appears in the diagram; if there is no relationship, no arrows will be shown.

2.5 Jump to Source Code

Double‑click a class in the diagram to open its source, then right‑click a method and choose Jump to Source . You can also use the Structure view on the left to navigate quickly between methods.

3. Conclusion

Using these IntelliJ IDEA features makes learning and exploring class relationships, especially for large frameworks, much more comfortable and efficient.