Fork run directly with 'java' to avoid additional class loader from 'scala' command. Fixes #702.

run/src/main/scala/sbt/Run.scala

@@ -24,7 +24,8 @@ class ForkRun(config: ForkOptions) extends ScalaRun
 
 		val scalaOptions = classpathOption(classpath) ::: mainClass :: options.toList
 		val configLogged = if(config.outputStrategy.isDefined) config else config.copy(outputStrategy = Some(LoggedOutput(log)))
-		val process =  Fork.scala.fork(configLogged, scalaOptions)
+		// fork with Java because Scala introduces an extra class loader (#702)
+		val process =  Fork.java.fork(configLogged, scalaOptions)
 		def cancel() = {
 			log.warn("Run canceled.")
 			process.destroy()

sbt/src/sbt-test/run/fork-loader/CheckLoader.scala

@@ -0,0 +1,8 @@
+object CheckLoader {
+	def main(args: Array[String]) { apply() }
+	def apply() {
+		val loader = getClass.getClassLoader
+		val appLoader = ClassLoader.getSystemClassLoader
+		assert(loader eq appLoader, "Application classes not loaded in the system class loader")
+	}
+}

sbt/src/sbt-test/run/fork-loader/build.sbt

@@ -0,0 +1,5 @@
+name := "forked-test"
+
+organization := "org.example"
+
+libraryDependencies += "org.scalacheck" %% "scalacheck" % "1.10.0" % "test"

sbt/src/sbt-test/run/fork-loader/src/test/scala/TestForked.scala

@@ -0,0 +1,8 @@
+import org.scalacheck._
+
+object TestForked extends Properties("Forked loader") {
+	property("Loaded from application loader") = Prop.secure {
+		CheckLoader()
+		true
+	}
+}

sbt/src/sbt-test/run/fork-loader/test

@@ -0,0 +1,6 @@
+# This test verifies that the forked code is loaded in the application class loader.
+-> run
+-> test
+> set fork := true
+> run
+> test