code: public boolean add(final Process process) {
      synchronized (processes) {
        // if this list is empty, register the shutdown hook
        if (processes.size() == 0) {
          try {
            if(shutDownHookExecuted) {
                throw new IllegalStateException();
            }
            addShutdownHook();
          }
          // kill the process now if the JVM is currently shutting down
          catch (IllegalStateException e) {
            destroy(process);
          }
        }
        processes.addElement(process);
        return processes.contains(process);
      }
    }
docs: Returns <code>true</code> if the specified <code>Process</code> was
  successfully added to the list of processes to destroy upon VM exit.
  
  @param process
  the process to add
  @return <code>true</code> if the specified <code>Process</code> was
  successfully added