Explore the challenges and solutions for upgrading to Java 9 and 10 in this 47-minute Devoxx conference talk. Learn about the new modularity system (Jigsaw), restrictions on internal library access, the JShell REPL, and the switch to G1 as the default garbage collector. Discover pragmatic strategies for migrating applications, including how to access restricted internal libraries, manage performance impacts, and implement a hybrid approach using both classpath and modularization. Gain insights on handling compatibility issues with Java EE libraries, updating build tools like Maven and Gradle, and addressing framework support for Spring and Apache Commons. Leave equipped with practical knowledge to confidently navigate the most significant changes since Java 5, ensuring a smooth transition to Java 9 and 10 for your projects.