-- using Activator 5.x and need to adjust Java Heap size
-- Changing Xmx value for EX_OPTIONS in bin\startserver does not work in Activator 5.10 or newer
-- Activator crash or restart with error:
java.lang.OutOfMemoryError: Java heap space
or
java.lang.OutOfMemoryError: GC overhead limit exceeded

Activator handles both UI and tradding in the same Java VM, unlike Interchange.  If you are getting out of memory errors in Activator, you do not adjust the TE or trading engine heap, you must adjust the EX or CN heap setting.

For Activator 5.9 and earlier:
There is only one JVM (EX).

Backup and then edit bin\startserver (using Windows service, bin\GatewayInterchangeService.ini)
modify Xmx and Xmx heap size values on the EX_NODE_OPTIONS line:
set EX_NODE_OPTIONS=-Xms256m -Xmx256m

For Activator 5.10 and later:
There is a small JVM (EX) that launches the main Activator JVM (CN). The bin\startserver  
"set EX_OPTIONS" line only controls the executive JVM, and does not affect the main JRE used by Activator 5.10.

You must backup and edit conf\jvmArguments.xml:
Find the section like this and modify Xms and Xmx values:
<NodeType type="CN" class="com.axway.clusterold.startup.Boot">
<Option>Xms256m</Option>
<Option>Xmx256m</Option>