Project Loom’s mission is to make it easier to write, debug, profile and maintain concurrent applications under heavy load. Threads are a natural and convenient concurrency construct which is being supplanted by less convenient abstractions because their implementation as OS kernel threads is insufficient for meeting performance demands and wasteful in computing resources. Project Loom will introduce fibers as lightweight, efficient threads managed by the Java Virtual Machine, that let developers use the same simple abstraction but with significantly better performance and lower footprint. Fibers are implemented in the JDK libraries on top of scoped, stackful delimited continuations in the JVM. This session will present the current status and challenges of the project -- both of implementation and design -- one year in.1