Explore the intricacies of incorporating RISC-V ISA into OpenJDK as we delve into the challenges and optimizations within a managed runtime environment. This FOSDEM talk explores the complexities of handling cross-modifying code and coping with the maze of RISC-V extensions. Additionally, we navigate multiple memory models, identify extensions through the hwprobe syscall, and delve into the need for trampolines. We look at the application of compressed instructions in the OpenJDK. Furthermore, we shed light on the default signed extension when crossing ABIs and dive into canonical NaN. Come and find out how to effectively use the RISC-V ISA!