org.vmmagic.pragma
Annotation Type Preemptible

@Retention(value=RUNTIME)
@Target(value={TYPE,METHOD})
public @interface Preemptible

By default all Java code is interruptible, that is scheduling or garbage collection may occur at points within the code. Code can be marked as 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.

value

public abstract String value

Returns:

Explanation of why code needs to be preemptible

Default:

""