C:\>scala Welcome to Scala version 2.10.0-M6 (Java HotSpot(TM) Client VM, Java 1.7.0_05). Type in expressions to have them evaluated. Type :help for more information. scala> var x : Int = 1 Failed to initialize the REPL due to an unexpected error. This is a bug, please, report it along with the error diagnostics printed below. java.util.concurrent.ExecutionException: java.util.regex.PatternSyntaxException: Unknown character property name {r} near index 5 ^C:\Program Files\Java\includes\.*.jar$ ^ at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source) at java.util.concurrent.FutureTask.get(Unknown Source) at scala.tools.nsc.interpreter.IMain.global$lzycompute(IMain.scala:194) at scala.tools.nsc.interpreter.IMain.global(IMain.scala:185) at scala.tools.nsc.interpreter.JLineCompletion.(JLineCompletion.scala:17) at scala.tools.nsc.interpreter.ILoop$$anonfun$chooseReader$1.apply(ILoop.scala:811) at scala.tools.nsc.interpreter.ILoop$$anonfun$chooseReader$1.apply(ILoop.scala:810) at scala.tools.nsc.interpreter.JLineReader.completion$lzycompute(JLineReader.scala:23) at scala.tools.nsc.interpreter.JLineReader.completion(JLineReader.scala:23) at scala.tools.nsc.interpreter.JLineReader$JLineConsoleReader.postInit$lzycompute(JLineReader.scala:57) at scala.tools.nsc.interpreter.JLineReader$JLineConsoleReader.postInit(JLineReader.scala:52) at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1$$anonfun$apply$mcZ$sp$1.apply$mcV$sp(ILoop.scala:829) at scala.tools.nsc.interpreter.ILoopInit$class.runThunks(ILoopInit.scala:123) at scala.tools.nsc.interpreter.ILoop.runThunks(ILoop.scala:42) at scala.tools.nsc.interpreter.ILoopInit$class.postInitialization(ILoopInit.scala:94) at scala.tools.nsc.interpreter.ILoop.postInitialization(ILoop.scala:42) at scala.tools.nsc.interpreter.ILoopInit$$anonfun$createAsyncListener$1.apply$mcV$sp(ILoopInit.scala:62) at scala.tools.nsc.interpreter.ILoopInit$$anonfun$createAsyncListener$1.apply(ILoopInit.scala:59) at scala.tools.nsc.interpreter.ILoopInit$$anonfun$createAsyncListener$1.apply(ILoopInit.scala:59) at scala.tools.nsc.io.package$$anon$3.call(package.scala:23) at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.util.regex.PatternSyntaxException: Unknown character property name {r} near index 5 ^C:\Program Files\Java\includes\.*.jar$ ^ at java.util.regex.Pattern.error(Unknown Source) at java.util.regex.Pattern.charPropertyNodeFor(Unknown Source) at java.util.regex.Pattern.family(Unknown Source) at java.util.regex.Pattern.sequence(Unknown Source) at java.util.regex.Pattern.expr(Unknown Source) at java.util.regex.Pattern.compile(Unknown Source) at java.util.regex.Pattern.(Unknown Source) at java.util.regex.Pattern.compile(Unknown Source) at scala.util.matching.Regex.(Regex.scala:153) at scala.collection.immutable.StringLike$class.r(StringLike.scala:224) at scala.collection.immutable.StringOps.r(StringOps.scala:31) at scala.collection.immutable.StringLike$class.r(StringLike.scala:213) at scala.collection.immutable.StringOps.r(StringOps.scala:31) at scala.tools.nsc.util.ClassPath$.scala$tools$nsc$util$ClassPath$$expandS(ClassPath.scala:42) at scala.tools.nsc.util.ClassPath$$anonfun$expandPath$1.apply(ClassPath.scala:75) at scala.tools.nsc.util.ClassPath$$anonfun$expandPath$1.apply(ClassPath.scala:75) at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:245) at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:245) at scala.collection.LinearSeqOptimized$class.foreach(LinearSeqOptimized.scala:59) at scala.collection.immutable.List.foreach(List.scala:78) at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:245) at scala.collection.AbstractTraversable.flatMap(Traversable.scala:105) at scala.tools.nsc.util.ClassPath$.expandPath(ClassPath.scala:75) at scala.tools.nsc.util.ClassPath$ClassPathContext.classesInPathImpl(ClassPath.scala:146) at scala.tools.nsc.util.ClassPath$ClassPathContext.classesInExpandedPath(ClassPath.scala:140) at scala.tools.util.PathResolver$Calculated$.basis(PathResolver.scala:229) at scala.tools.util.PathResolver$Calculated$.containers$lzycompute(PathResolver.scala:233) at scala.tools.util.PathResolver$Calculated$.containers(PathResolver.scala:233) at scala.tools.util.PathResolver.containers(PathResolver.scala:255) at scala.tools.util.PathResolver.result$lzycompute(PathResolver.scala:258) at scala.tools.util.PathResolver.result(PathResolver.scala:257) at scala.tools.nsc.backend.JavaPlatform$class.classPath(JavaPlatform.scala:23) at scala.tools.nsc.Global$$anon$3.classPath(Global.scala:96) at scala.tools.nsc.backend.JavaPlatform$class.rootLoader(JavaPlatform.scala:31) at scala.tools.nsc.Global$$anon$3.rootLoader(Global.scala:96) at scala.tools.nsc.Global$$anon$3.rootLoader(Global.scala:96) at scala.tools.nsc.Global$GlobalMirror.rootLoader(Global.scala:54) at scala.reflect.internal.Mirrors$Roots$RootClass$.(Mirrors.scala:275) at scala.reflect.internal.Mirrors$Roots.RootClass$lzycompute(Mirrors.scala:274) at scala.reflect.internal.Mirrors$Roots.RootClass(Mirrors.scala:274) at scala.reflect.internal.Mirrors$Roots$EmptyPackageClass$.(Mirrors.scala:286) at scala.reflect.internal.Mirrors$Roots.EmptyPackageClass$lzycompute(Mirrors.scala:286) at scala.reflect.internal.Mirrors$Roots.EmptyPackageClass(Mirrors.scala:286) at scala.reflect.internal.Mirrors$Roots.EmptyPackageClass(Mirrors.scala:241) at scala.reflect.internal.Mirrors$RootsBase.init(Mirrors.scala:230) at scala.tools.nsc.Global.rootMirror$lzycompute(Global.scala:60) at scala.tools.nsc.Global.rootMirror(Global.scala:58) at scala.tools.nsc.Global.rootMirror(Global.scala:36) at scala.reflect.internal.Definitions$DefinitionsClass.(Definitions.scala:172) at scala.reflect.internal.Definitions$definitions$.(Definitions.scala:20) at scala.reflect.internal.SymbolTable.definitions$lzycompute(SymbolTable.scala:12) at scala.reflect.internal.SymbolTable.definitions(SymbolTable.scala:12) at scala.tools.nsc.Global$Run.(Global.scala:1284) at scala.tools.nsc.interpreter.IMain.scala$tools$nsc$interpreter$IMain$$_initialize(IMain.scala:157) at scala.tools.nsc.interpreter.IMain$$anonfun$initialize$1.apply$mcZ$sp(IMain.scala:170) at scala.tools.nsc.interpreter.IMain$$anonfun$initialize$1.apply(IMain.scala:170) at scala.tools.nsc.interpreter.IMain$$anonfun$initialize$1.apply(IMain.scala:170) ... 6 more .