Hiring a Java developer is beneficial due to Java's robustness, security, and cross-platform capabilities. Java developers can build complex and efficient enterprise-grade applications, web and mobile apps, and software systems. They have a strong grasp of object-oriented principles, which helps in creating modular applications with high maintainability. Java's widespread use in the industry also means a large community and numerous resources for problem-solving. Furthermore, Java developers often have knowledge of key tools and frameworks like Spring, Hibernate, or Maven, which can significantly speed up the development process.