Index: src/builtin/jsignal.rb
===================================================================
--- src/builtin/jsignal.rb      (revision 4868)
+++ src/builtin/jsignal.rb      (working copy)
@@ -7,6 +7,9 @@
     26 => "SIGVTALRM", 27 => "SIGPROF", 30 => "SIGUSR1", 31 => "SIGUSR2"
   }
   begin
+    # attempt to load the Signal handler from Sun JVM, falling back to a dummy impl below
+    Java::sun.misc.Signal
+    
     def __jtrap(*args, &block)
       sig = args.first
       sig = SIGNALS[sig] if sig.kind_of?(Fixnum)