What Should I Learn to Get a 200% Salary Hike as a Java + React Full-Stack Developer?

I've been working as a Full-Stack Developer with Java (Spring Boot) and React.js, and I'm trying to figure out the most valuable skills to learn over the next 6–12 months.

The goal isn't just to switch jobs—it's to land a role that offers a significant salary jump (150–200%+) and work on products that solve real-world problems at scale.

Here's what I'm considering:

• Java 21 & Spring Boot 3
• Microservices Architecture
• System Design (LLD + HLD)
• AWS (EC2, S3, RDS, Lambda, ECS)
• Docker & Kubernetes
• Apache Kafka
• Redis
• PostgreSQL Performance Tuning
• CI/CD (GitHub Actions, Jenkins)
• React Performance Optimization
• Next.js
• TypeScript
• GraphQL
• Security (JWT, OAuth2, Spring Security)
• Design Patterns & Clean Architecture
• AI-assisted Development (GitHub Copilot, ChatGPT, Cursor)

I'm also planning to spend more time on:

• Solving DSA problems for product-based companies.
• Building production-grade side projects instead of basic CRUD apps.
• Contributing to open-source projects.
• Writing technical blogs and documenting what I learn.
• Preparing for System Design interviews.

My Questions

1. If you were hiring today, which skills would make a Java + React developer stand out?
2. Which technologies have had the biggest impact on your salary growth?
3. If you had 6 months to prepare for top-paying product companies, what would you focus on?
4. What common mistakes keep developers from reaching the next salary level?

I'd love to hear your experiences and recommendations.

Thanks in advance! 🚀