RFR[ 9u-dev] JDK-8129348: Debugger hangs in trace mode with TRACE_SENDS

[cheleswer sahu]

Hi,

Please review the code changes for "https://bugs.openjdk.java.net/browse/JDK-8129348".
Web review link: http://cr.openjdk.java.net/~kevinw/8129348/webrev.01/

Bug Brief: Debugger hangs in trace mode when TRACE_SENDS flag is enabled. To print the argument information, it does a remote call from a
synchronized method which causes a deadlock .

Fix proposed:
Cache the value of args by calling the toString() method on args before entering into synchronized method. This cached values can be used later
to print the values when needed and avoid deadlock.
The bug is introduced in build time generated code (JDWP.java), and changing the generator code is problematic so cache value has been chosen as a solution.
  

Regards,
Cheleswer