Spring Authorization Server Custom OTP Grant Fix | OAuth2 Token Generator Explained
In this video, we dive deep into Spring Authorization Server and understand why your Custom OTP Grant is failing at the /oauth2/token endpoint.
If you are getting issues like:
UsernamePasswordAuthenticationToken not working
ClassCastException during token generation
OAuth2 token not generating
Custom grant type failing
Then this video will help you understand the exact root cause and fix.
We will cover:
✔ Why Spring expects OAuth2AccessTokenAuthenticationToken
✔ Internal working of OAuth2TokenEndpointFilter
✔ How Token Generation works internally
✔ OAuth2TokenGenerator interface explained
✔ JWKSource and JWT signing (Public/Private Keys)
✔ JwtGenerator vs OAuth2AccessTokenGenerator
✔ DelegatingOAuth2TokenGenerator (Real Purpose)
✔ Fixing Custom OTP Grant step-by-step
This is part of our Real-World Banking Application Series using Spring Boot and Spring Security OAuth2.
Perfect for:
Spring Boot Developers
Backend Developers
Java Interview Preparation
System Design Learners
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Keywords:
spring authorization server custom grant
oauth2 token generator spring boot
jwt generator spring security
delegatingoauth2tokengenerator explained
spring security oauth2 token flow
custom otp login spring boot
classcastexception oauth2 spring fix
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