--- a/langtools/src/jdk.jshell/share/classes/jdk/internal/jshell/remote/RemoteCodes.java	Tue Mar 22 13:14:12 2016 +0100
+++ b/langtools/src/jdk.jshell/share/classes/jdk/internal/jshell/remote/RemoteCodes.java	Mon Apr 25 08:50:16 2016 -0700
@@ -47,8 +47,12 @@
     public static final int RESULT_CORRALLED = 103;
     public static final int RESULT_KILLED    = 104;
 
+    // String constants
+    public static final String REPL_PACKAGE = "REPL";
+    public static final String REPL_CLASS_PREFIX = "$JShell$";
     public static final String DOIT_METHOD_NAME = "do_it$";
-    public static final String replClass = "\\$REPL(?<num>\\d+)[A-Z]*";
-    public static final Pattern prefixPattern = Pattern.compile("(REPL\\.)?" + replClass + "[\\$\\.]?");
-
+    public static final Pattern PREFIX_PATTERN = Pattern.compile(
+            "(" + REPL_PACKAGE + "\\.)?" +
+            "(?<class>" + Pattern.quote(REPL_CLASS_PREFIX) +
+            "\\w+" + ")" + "[\\$\\.]?");
 }