Index: src/org/jruby/RubyInstanceConfig.java
===================================================================
--- src/org/jruby/RubyInstanceConfig.java	(revision 6595)
+++ src/org/jruby/RubyInstanceConfig.java	(working copy)
@@ -299,6 +299,8 @@
                 //.append("  -x[directory]   strip off text before #!ruby line and perhaps cd to directory\n")
                 .append("  -X[option]      enable extended option (omit option to list)\n")
                 .append("  --copyright     print the copyright\n")
+                .append("  --debug         must be used for debugger functionality\n")
+                .append("  --jdb           runs JRuby process under JDB\n")
                 .append("  --properties    List all configuration Java properties (pass -J-Dproperty=value)\n")
                 .append("  --version       print the version\n");
 
@@ -831,6 +833,10 @@
                         shouldRunInterpreter = false;
                         break FOR;
                     } else if (argument.equals("--debug")) {
+                        compileMode = CompileMode.OFF;
+                        System.setProperty("jruby.reflection", "true");
+                        break FOR;
+                    } else if (argument.equals("--jdb")) {
                         debug = true;
                         verbose = Boolean.TRUE;
                         break;
Index: bin/jruby
===================================================================
--- bin/jruby	(revision 6595)
+++ bin/jruby	(working copy)
@@ -113,7 +113,7 @@
      # Run with the instrumented profiler: http://jiprof.sourceforge.net/
      --profile) PROFILE_ARGS="-javaagent:$JRUBY_HOME/lib/profile.jar -Dprofile.properties=$JRUBY_HOME/lib/profile.properties" ;;
      # Run under JDB
-     --debug)
+     --jdb)
         if [ -z "$JAVA_HOME" ] ; then
           JAVA_CMD='jdb'
         else
@@ -171,4 +171,4 @@
     "-Djruby.lib=$JRUBY_HOME/lib" -Djruby.script=jruby \
     "-Djruby.shell=$JRUBY_SHELL" \
     org.jruby.Main $JRUBY_OPTS "$@"
-fi
\ No newline at end of file
+fi