to reproduce, go to Java Control Panel > Java Tab > View... > Runtime
 Parameters
 add this sting and save:
 -agentlib:jdwp=transport=dt_socket,address=2502,server=y,suspend=n
 launch a java applet in any browser.
 attempt to remote debug from any IDE.
 From eclipse you can do these steps:
 Debug Configurations > New Remote Java Application > Connect tab
 Connection Type: Standard(Socket Attach)
 Host: localhost (assuming that you're running browser & applet on same system
 you're debugging from, else use system name or IP address)
 Port: 2502 (just make sure it matches Java Runtime Parameters)
 Apply and debug.
 .
 I found this worked on Java 1.7_17 64 bit and 32 bit
 uninstalled all versions of Java and installed Java 1.7_21 64 bit and 32 bit
 .
 these same steps to debug no longer work, connection will be refused.
 .
 once again uninstalled all versions of java and installed Java 1.7_17 64 bit
 and 32 bit.
 .
 Once again I'm able to debug
 .
 Impact: This is preventing developers from updating their systems to Java
 1.7_21 and we're forced to stay on Java 1.7_17. We're unable to take the
 latest(and most secure) Java version.