You added the springdoc-openapi-starter-webmvc-ui dependency but when you run your Spring Boot app, the Swagger UI page shows a 404 error. What is the most likely cause?
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Spring Boot - API Documentation
You added the springdoc-openapi-starter-webmvc-ui dependency but when you run your Spring Boot app, the Swagger UI page shows a 404 error. What is the most likely cause?
AYou are trying to access the Swagger UI at the wrong URL
BYou did not include the <code>springdoc-openapi-starter-webmvc-ui</code> dependency correctly
CYou have not defined an OpenAPI bean in your configuration
DYou forgot to add the <code>@SpringBootApplication</code> annotation
Step-by-Step Solution
Solution:
Step 1: Check common reasons for 404 on Swagger UI
Missing dependency or wrong annotation usually cause app startup errors, not 404 on UI page.
Step 2: Verify URL correctness
Swagger UI default URL is /swagger-ui/index.html, accessing other URLs like /swagger-ui.html causes 404.
Final Answer:
You are trying to access the Swagger UI at the wrong URL -> Option A
Quick Check:
404 on Swagger UI usually means wrong URL [OK]
Quick Trick:Check Swagger UI URL carefully if 404 occurs [OK]
Common Mistakes:
Assuming missing OpenAPI bean causes 404
Thinking missing @SpringBootApplication causes 404 instead of startup failure
Ignoring URL path correctness
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