@Retention(value=RUNTIME) @Target(value={TYPE,METHOD}) public @interface Preemptible
Unpreemptible or Uninterruptible, that instructs the JVM to
avoid garbage collection and thread scheduling. The Uninterruptible
annotation disallows any operation that may cause garbage collection or
thread scheduling, for example memory allocation. The Unpreemptible
annotation doesn't disallow operations that can cause garbage collection or
scheduling, but instructs the JVM to avoid inserting such operations during a
block of code.
In the internals of a VM most code wants to be Uninterruptible.
However, code involved in scheduling and locking will cause context switches,
and creating exception objects may trigger garbage collection, this code is
therefore Unpreemptible.
This pragma is used to declare that a particular method is preemptible. It
is used to override the class-wide pragma Unpreemptible.