Stopping and starting WAS application modules separately via wsadmin

Allow starting and stopping an individual Web or EJB modules using an undocumented call to the ApplicationManager object.

Get a reference to the relevant ApplicationManager object in the usual way:

appManager = AdminControl.queryNames

('type=ApplicationManager,process=myClusterMember1,node=myNode,*')

List the operations available for the appManager object...

print Help.operations(appManager)

This results in the following output …

void startApplication(java.lang.String)  
java.lang.Boolean _canStopApplication(java.lang.String) 
void stopApplication(java.lang.String) 
void _startModule(java.lang.String, java.lang.String) 
void _stopModule(java.lang.String, java.lang.String) 
void _applicationInstalled(java.lang.String) 
void _applicationUninstalled(java.lang.String)

The two methods we're interested in are  _startModule and _stopModule, both of which take two arguments of type String.

True to form the IBM documentation was awful.

print Help.operations(appManager, '_startModule')

Provides the following following output:

void _startModule(java.lang.String, java.lang.String)
Description: Start Application Module - This method is intended for WebSphere internal use only.  Its function is undocumented and is subject to change at any time.

Parameters:
Type  java.lang.String
Name  applicationName
Description  Application Name

Type  java.lang.String
Name  moduleURI
Description  Module Name 

It took me a while to work out how to format the arguments, here's the correct form:

AdminControl.invoke(<reference to app manager>, '<action>', '<app name> <module name>')

For example:

AdminControl.invoke(appManager,  '_startModule',  'MyApp  MyWebModule' )

As you can see, there are three arguments as follows:
- The reference to the ApplicationManager object
- The action
- A string which is the application name concatenated with the module name (separated by a space)

So, a nice easy way to do this would be:

appManager = AdminControl.queryNames('type=ApplicationManager,process=server1,node=node1,*')
appName = 'MyApp'
moduleName = 'MyWebModule'
args = appName + '  ' + moduleName
adminControl.invoke(appManager,  '_startModule',  args )

I also found out that if you're using a later wsadmin client (e.g. the one that ships with WAS 8.5 and above) that the third argument can be an array:

AdminControl.invoke(appManager,  '_startModule' ,  ['MyApp' , 'MyWebModule'] )

Here's an example of how I used this in the real world when I needed to start a WebModule after hot deploying it.