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I will fix java spring boot bugs, cors errors and backend issues
Yaseen P
About this gig
Is your Java Spring Boot application throwing errors or not working as expected?
I will debug and fix bugs in your Java Spring Boot backend and help get your application working correctly.
I can help with:
Spring Boot errors
REST API bugs
Spring Security & JWT issues
JPA / Hibernate errors
MySQL & database problems
Entity relationship & mapping issues
CORS errors
401 / 403 authentication problems
NullPointerException and runtime errors
CRUD API issues
Validation errors
Exception handling
Docker / deployment-related backend issues
API testing problems with Postman
What you will receive:
Properly fixed code
Explanation of the problem and solution
Clean and maintainable implementation
Testing of the fixed functionality
Source-code changes
I work with Java, Spring Boot, Spring Security, JWT, JPA/Hibernate, MySQL, REST APIs, Docker and AWS.
Have a bug that you're not sure about?
Message me before placing an order and send me the error message, relevant code, or a short explanation of the problem. I'll check whether I can help and recommend the appropriate package.
Get to know Yaseen P
Yaseen P
Java Backend Developer
- FromIndia
- Member sinceSep 2026
- Avg. response time1 hour
Languages
English
I am a Java Backend Developer and BCA graduate with hands-on experience designing, building, and deploying distributed backend systems. I have built and live-deployed a 7-service Spring Boot microservices platform utilizing AWS, Docker, and JWT-based security. I specialize in optimizing scalable applications and implementing event-driven processing.
Other Software Development Services I Offer
FAQ
How do you fix CORS errors between my frontend and Spring Boot backend?
To resolve a cors error, I configure custom CorsFilter beans or WebMvcConfigurer settings with proper allowedOrigins, headers, and HTTP methods. This ensures smooth communication with frontend clients like React, Angular, Vue, or mobile apps without breaking security rules or throwing cros
What common Spring Security and authentication bugs can you fix?
I specialize in solving spring security issues, including 401 Unauthorized, 403 Forbidden, broken JWT token generation, expired claims, and migration headaches in Spring Security 6 (SecurityFilterChain). I will debug java authentication flows to ensure secure endpoint access.
What information do you need to debug Java and fix Spring Boot bugs quickly?
To quickly fix spring boot issues, please provide the full terminal console log, the exact stack trace, the relevant controller or service code, and details about your Java and Spring Boot versions. Once I review the error log, I can reproduce the backend bug and deliver a fast fix.
How fast can you resolve an urgent backend bug or runtime exception?
Most single-issue errors—such as a database mapping failure, NullPointerException, or configuration backend bug—can be diagnosed and fixed within 24 hours under the Basic package. For production-critical emergencies, send a direct message for immediate assistance.
What types of Java and Spring Boot errors do you handle?
I handle a complete range of issues: BeanCreationException, circular dependency problems, JPA/Hibernate LazyInitializationException, broken REST API endpoints, Maven/Gradle build conflicts, and third-party API integration errors across Java 8, 11, 17, and 21.
