A Java SDK developer designs, develops, and maintains software applications using the Java programming language and Software Development Kit (SDK). They are responsible for writing clean, efficient code and debugging any issues that arise. They often collaborate with other developers, architects, and clients to understand requirements, design software solutions, and implement them effectively. They also test and improve the software to ensure its quality and performance. Furthermore, they often document their code and create user manuals, ensuring the software is user-friendly and easy to maintain. They stay updated with the latest Java and SDK trends to optimize their work.