4 files changed, 164 insertions, 9 deletions
diff --git a/src/library/scala/Predef.scala b/src/library/scala/Predef.scala
index 491d9e3901..7237c628d0 100644
--- a/src/library/scala/Predef.scala
+++ b/src/library/scala/Predef.scala
@@ -58,17 +58,14 @@ object Predef extends LowPriorityImplicits {
 
   // errors and asserts -------------------------------------------------
 
-  // @deprecated("Throw your own exceptions") // deprecation waiting for 2.9
-  def error(message: String): Nothing = throw new RuntimeException(message)
+  @deprecated("Use system.error(message) instead")
+  def error(message: String): Nothing = system.error(message)
 
-  // @deprecated("Use System.exit instead") // deprecation waiting for 2.9
-  def exit(): Nothing = exit(0)
+  @deprecated("Use system.exit() instead")
+  def exit(): Nothing = system.exit()
 
-  // @deprecated("Use System.exit(status) instead") // deprecation waiting for 2.9
-  def exit(status: Int): Nothing = {
-    java.lang.System.exit(status)
-    throw new Throwable()
-  }
+  @deprecated("Use system.exit(status) instead")
+  def exit(status: Int): Nothing = system.exit(status)
 
   /** Tests an expression, throwing an AssertionError if false.
    *  Calls to this method will not be generated if -Xelide-below
diff --git a/src/library/scala/system/PropertiesMap.scala b/src/library/scala/system/PropertiesMap.scala
new file mode 100644
index 0000000000..a01eee6931
--- /dev/null
+++ b/src/library/scala/system/PropertiesMap.scala
@@ -0,0 +1,31 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.system
+
+import scala.collection.mutable
+import scala.collection.JavaConverters._
+
+/** A bidirectional map wrapping the java System properties.
+ *  Changes to System properties will be immediately visible in the map,
+ *  and modifications made to the map will be immediately applied to the
+ *  System properties.
+ *
+ *  @author Paul Phillips
+ *  @version 2.9
+ *  @since   2.9
+ */
+class PropertiesMap extends mutable.Map[String, String] {
+  override def empty = new PropertiesMap
+  override def default(key: String): String = null
+  def iterator: Iterator[(String, String)] = System.getProperties().asScala.iterator
+  def get(key: String) = Option(System.getProperty(key))
+
+  def -= (key: String): this.type = { System.clearProperty(key) ; this }
+  def += (kv: (String, String)): this.type = { System.setProperty(kv._1, kv._2) ; this }
+}
+\ No newline at end of file
diff --git a/src/library/scala/system/ShutdownHookThread.scala b/src/library/scala/system/ShutdownHookThread.scala
new file mode 100644
index 0000000000..17a5e398ef
--- /dev/null
+++ b/src/library/scala/system/ShutdownHookThread.scala
@@ -0,0 +1,39 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.system
+
+/** A minimal Thread wrapper to enhance shutdown hooks.  It knows
+ *  how to unregister itself.
+ *
+ *  @author Paul Phillips
+ *  @version 2.9
+ *  @since   2.9
+ */
+class ShutdownHookThread private (name: String) extends Thread(name) {
+  def remove() = runtime removeShutdownHook this
+}
+
+object ShutdownHookThread {
+  private var hookNameCount: Int = 0
+  private def hookName(): String = synchronized {
+    hookNameCount += 1
+    "shutdownHook" + hookNameCount
+  }
+  /** Creates, names, and registers a shutdown hook to run the
+   *  given code.
+   */
+  def apply(body: => Unit): ShutdownHookThread = {
+    val t = new ShutdownHookThread(hookName()) {
+      override def run() = body
+    }
+    t setDaemon true
+    runtime addShutdownHook t
+    t
+  }
+}
diff --git a/src/library/scala/system/package.scala b/src/library/scala/system/package.scala
new file mode 100644
index 0000000000..4dc754d373
--- /dev/null
+++ b/src/library/scala/system/package.scala
@@ -0,0 +1,88 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala
+
+import scala.collection.immutable
+import collection.JavaConverters._
+
+/** The package object `scala.system` contains methods for reading
+ *  and altering core aspects of the virtual machine as well as the
+ *  world outside of it.
+ *
+ *  @author Paul Phillips
+ *  @version 2.9
+ *  @since   2.9
+ */
+package object system {
+  /** Throw a new RuntimeException with the supplied message.
+   *
+   *  @return   Nothing.
+   */
+  def error(message: String): Nothing = throw new RuntimeException(message)
+
+  /** Exit the JVM with the default status code.
+   *
+   *  @return   Nothing.
+   */
+  def exit(): Nothing = exit(0)
+
+  /** Exit the JVM with the given status code.
+   *
+   *  @return   Nothing.
+   */
+  def exit(status: Int): Nothing = {
+    java.lang.System.exit(status)
+    throw new Throwable()
+  }
+
+  /** A convenience method to get the current Runtime instance.
+   *
+   *  @return   the result of `java.lang.Runtime.getRuntime()`
+   */
+  def runtime: Runtime = Runtime.getRuntime
+
+  /** A bidirectional, mutable Map representing the current system Properties.
+   *
+   *  @return   a PropertiesMap.
+   *  @see      `scala.system.PropertiesMap`
+   */
+  def props: PropertiesMap = new PropertiesMap
+
+  /** An immutable Map representing the current system environment.
+   *
+   *  @return   a Map containing the system environment variables.
+   */
+  def env: immutable.Map[String, String] = immutable.Map(System.getenv().asScala.toSeq: _*)
+
+  /** Register a shutdown hook to be run when the VM exits.
+   *  The newly created thread is marked as a daemon so it will not
+   *  interfere with VM shutdown.  The hook is automatically registered:
+   *  the returned value can be ignored, but is available in case the
+   *  Thread requires further modification.  It can also be unregistered
+   *  by calling ShutdownHookThread#remove().
+   *
+   *  Note that shutdown hooks are NOT guaranteed to be run.
+   *
+   *  @param    the body of code to run at shutdown
+   *  @return   the Thread which will run the shutdown hook.
+   */
+  def addShutdownHook(body: => Unit): Thread = ShutdownHookThread(body)
+
+  /** Returns all active thread in the current thread's thread group and subgroups.
+   *
+   *  @return   an IndexedSeq containing the threads.
+   */
+  def allThreads(): IndexedSeq[Thread] = {
+    val num    = Thread.activeCount()
+    val tarray = new Array[Thread](num)
+    val got    = Thread.enumerate(tarray)
+
+    tarray take got
+  }
+}
+\ No newline at end of file