updated version information;
discontinued somewhat obsolete hotspot check: OpenJDK 1.7 works reasonably well, and final bundling provides certain tested JDK/JRE versions;

--- a/src/Pure/System/platform.scala	Wed Jan 04 13:58:06 2012 +0100
+++ b/src/Pure/System/platform.scala	Wed Jan 04 15:41:18 2012 +0100
@@ -58,7 +58,6 @@
   /* JVM name */
 
   val jvm_name: String = System.getProperty("java.vm.name")
-  val is_hotspot: Boolean = jvm_name.startsWith("Java HotSpot")
 
 
   /* Swing look-and-feel */

--- a/src/Tools/jEdit/README_BUILD	Wed Jan 04 13:58:06 2012 +0100
+++ b/src/Tools/jEdit/README_BUILD	Wed Jan 04 15:41:18 2012 +0100
@@ -1,11 +1,14 @@
 Requirements for instantaneous build from sources
 =================================================
 
-* Official Java JDK 1.6/1.7 from Sun/Oracle/Apple
+* Official Java JDK 1.6 from Sun/Oracle/Apple
   http://www.oracle.com/technetwork/java/javase/downloads/index.html
 
-* Scala 2.8.2.final (experimental support for 2.9.1.final)
-  http://www.scala-lang.org
+  (experimental support for JDK/OpenJDK 1.7)
+
+* Scala 2.8.2.final http://www.scala-lang.org
+
+  (experimental support for 2.9.1.final)
 
 * Auxiliary jedit_build component
   http://www4.in.tum.de/~wenzelm/test/jedit_build-20111217.tar.gz

--- a/src/Tools/jEdit/src/plugin.scala	Wed Jan 04 13:58:06 2012 +0100
+++ b/src/Tools/jEdit/src/plugin.scala	Wed Jan 04 15:41:18 2012 +0100
@@ -150,18 +150,6 @@
   }
 
 
-  /* check JVM */
-
-  def check_jvm()
-  {
-    if (!Platform.is_hotspot) {
-      Library.warning_dialog(jEdit.getActiveView, "Bad Java Virtual Machine",
-        "This is " + Platform.jvm_name,
-        "Isabelle/jEdit requires Java Hotspot from Sun/Oracle/Apple!")
-    }
-  }
-
-
   /* buffers */
 
   def swing_buffer_lock[A](buffer: JEditBuffer)(body: => A): A =
@@ -433,7 +421,6 @@
     Swing_Thread.assert()
     message match {
       case msg: EditorStarted =>
-        Isabelle.check_jvm()
         if (Isabelle.Boolean_Property("auto-start"))
           Isabelle.start_session()