JRebel is a tool that eliminates redeploys for Java developers, allowing them to immediately see changes to code without rebuilding and redeploying projects. This saves significant time otherwise spent waiting for code changes to be reflected. Without JRebel, developers spend around 5 weeks per year waiting for redeploys, reducing productivity. JRebel pays for itself with the average return on investment being around 2 weeks of developer time saved. By eliminating redeploys, JRebel improves developer focus and productivity.