--- a/jdk/src/share/classes/sun/misc/ProxyGenerator.java	Tue Aug 30 14:41:12 2011 +0100
+++ b/jdk/src/share/classes/sun/misc/ProxyGenerator.java	Tue Aug 30 11:53:11 2011 -0700
@@ -460,7 +460,7 @@
             methods.add(generateStaticInitializer());
 
         } catch (IOException e) {
-            throw new InternalError("unexpected I/O Exception");
+            throw new InternalError("unexpected I/O Exception", e);
         }
 
         if (methods.size() > 65535) {
@@ -540,7 +540,7 @@
             dout.writeShort(0); // (no ClassFile attributes for proxy classes)
 
         } catch (IOException e) {
-            throw new InternalError("unexpected I/O Exception");
+            throw new InternalError("unexpected I/O Exception", e);
         }
 
         return bout.toByteArray();