diff -r bf01be7d1a44 -r e17a1f179bb0 src/Pure/library.scala
--- a/src/Pure/library.scala	Thu Dec 06 23:07:10 2012 +0100
+++ b/src/Pure/library.scala	Fri Dec 07 13:38:32 2012 +0100
@@ -10,6 +10,7 @@
 
 import java.lang.System
 import java.util.Locale
+import java.util.concurrent.{Future => JFuture, TimeUnit}
 import java.awt.Component
 import javax.swing.JOptionPane
 
@@ -187,6 +188,18 @@
     selection.index = 3
     prototypeDisplayValue = Some("00000%")
   }
+
+
+  /* Java futures */
+
+  def future_value[A](x: A) = new JFuture[A]
+  {
+    def cancel(may_interrupt: Boolean): Boolean = false
+    def isCancelled(): Boolean = false
+    def isDone(): Boolean = true
+    def get(): A = x
+    def get(timeout: Long, time_unit: TimeUnit): A = x
+  }
 }