Basic j-interop DCOM bridge setup snippets. Code for blog post https://fishi.devtail.io/weblog/2015/01/21/pure-java-dcom-bridge-j-interop/

ConnectWMINamespace.java

/**
 * Code snippet that tries to create a connection with the given wmiLocator object to the given namespace.
 * @return An IJIDispatch object that can be used for WQL queries to the given namesapce of the target machine.
 * @Exception In case the ConnectServer method could not be properly executed.
 */
public IJIDispatch createNamespaceServer(IJIDispatch wmiLocator, String nameSpace, String ipAddress) throws Exception
{
    // create an instance of the WbemScripting.SWbemLocator object to talk to WMI on the target machine.
    // namespace could be for instance "root\\cimv2"
    JIVariant results[] =
                bridge.getWbemLocator().callMethodA("ConnectServer", new Object[] { new JIString(ipAddress), new JIString(nameSpace),
                        JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), new Integer(0),
                        JIVariant.OPTIONAL_PARAM()});
    
    IJIDispatch wbemService = (IJIDispatch) JIObjectFactory.narrowObject(results[0].getObjectAsComObject());
    return wbemService;
}

CreateCOMServer.java

/**
 * Code snippet for creating a WbemScripting.SWbemLocator JIComServer through which queries to the WMI machine can be made. 
 * This method will only work, if a JISession is already established.    
 * @return A IJIDispatch object through which represents the WbemScripting.SWbemLocator class on the target machine.
 * @throws Exception if WbemScripting.SWbemLocator could not be created
 */
private IJIDispatch createWmiLocator(JISession dcomSession) throws Exception
{
    JIComServer wbemLocatorComObj = new JIComServer(JIClsid.valueOf("76A64158-CB41-11D1-8B02-00600806D9B6"), MyDefaults.IP_ADDR, dcomSession);
    IJIDispatch wmiLocator = (IJIDispatch) JIObjectFactory.narrowObject(wbemLocatorComObj.createInstance().queryInterface(IJIDispatch.IID));
    return wmiLocator;
}

CreateDCOMSession.java

/**
 * Code snippet for establishing a DCOM Session (JISession) which is the initial step in creating DCOM bridge
 * @return A functional DCOM session
 * @throws Exception if the DCOM session could not be created
 */
private JISession createDComSession(String domain, String user, String password) throws Exception
{
    /**
    * Please note that the user must have administrator permissions on the target Windows machine
    */
    JISession dcomSession = JISession.createSession(domain, user, password);

    /**
     *  NTLM1 config
     */
    dcomSession.useSessionSecurity(true);

    /**
     * Set the socket timeout for connections in this session.
     * This is very important - in case the other end shuts down, 
     * infinite blocking may occur... 
     */
    dcomSession.setGlobalSocketTimeout(MyDefaults.DCOM_SOCKET_TO);

    return dcomSession;
}

QueryCounters.java

/**
 * Code snippet for querying Disk IO performance from target machine and print to output.
 * @Exception In case something goes wrong during query processing
 */
public void printDiskIO(IJIDispatch wbemService) throws Exception
{
    /** 
     * The WQL query.
     * WMI Classes are stored in a table. 
     */
    final String QUERY = "SELECT * FROM Win32_PerfFormattedData_PerfDisk_PhysicalDisk";
            
    /**
     * Flags for the query.
     */
    final int RETURN_IMMEDIATE = 16;
    final int FORWARD_ONLY = 32;
            
    /**
     * Execute the query
     */
    JIVariant[] sourceSet = wbemService.callMethodA("ExecQuery", new Object[] { new JIString(QUERY), new JIString("WQL"), new JIVariant(new Integer(RETURN_IMMEDIATE + FORWARD_ONLY))});
    IJIDispatch wbemSource = (IJIDispatch) JIObjectFactory.narrowObject((sourceSet[0]).getObjectAsComObject());
    IJIComObject enumSet = wbemSource.get("_NewEnum").getObjectAsComObject();
    IJIEnumVariant enumVariant = (IJIEnumVariant) JIObjectFactory.narrowObject(enumSet.queryInterface(IJIEnumVariant.IID));
            
    /** 
     * Process the result
     */
    Object[] values = enumVariant.next(1);
    JIArray array = (JIArray) values[0];
    Object[] arrayObj = (Object[])array.getArrayInstance();
    
    /**
    * Loop through each found disk
    */
    for (int j = 0; j < arrayObj.length; j++)
    {
        IJIComObject procComObj = ((JIVariant)arrayObj[j]).getObjectAsComObject();
        IJIDispatch wbemProcObj = (IJIDispatch) JIObjectFactory.narrowObject(procComObj);
                        
        /** 
         * Print all the info from the current disk
         */
        String txt = getObjectResults.getObjectAsString().getString();
        System.out.println(txt);
        System.out.println();
    }
}

WMIEventListener.java

/**
 * Code snippet for listening to events from Windows Event Viewer that have the given event code.
 * Print the information from each received event to the output.
 */
public void listen(IJIDispatch wbemService, String eventCode)
{
    final String QUERY_FOR_ALL_LOG_EVENTS = "SELECT\ *\ FROM\ __InstanceCreationEvent\ WITHIN\ 5\ WHERE\ TargetInstance\ ISA\ 'Win32_NTLogEvent' AND TargetInstance.EventCode = '"+eventCode+"'";
    
    final int RETURN_IMMEDIATE = 16;
    final int FORWARD_ONLY = 32;
    
    /**
     * Subscribe.
     */
    JIVariant[] eventSourceSet = wbemService.callMethodA("ExecNotificationQuery", new Object[] { new JIString(QUERY_FOR_ALL_LOG_EVENTS), new JIString("WQL"), new JIVariant( new Integer(RETURN_IMMEDIATE + FORWARD_ONLY))});
    IJIDispatch wbemEventSource = (IJIDispatch) JIObjectFactory.narrowObject((eventSourceSet[0]).getObjectAsComObject());
    
    /**
     * Start the listening loop
     */        
    while(true)
    {
        /** 
         * Note, this blocks until an event as specified by the query occurs!
         */
        JIVariant eventAsVariant = (JIVariant) (wbemEventSource.callMethodA("NextEvent", new Object[] {JIVariant.OPTIONAL_PARAM()}))[0];
        IJIDispatch wbemEvent = (IJIDispatch) JIObjectFactory.narrowObject(eventAsVariant.getObjectAsComObject());
    
        /**
         * Process the received event
         */
        IJIComObject eventCom = eventAsVariant.getObjectAsComObject();
        IJIDispatch eventProcObj = (IJIDispatch) JIObjectFactory.narrowObject(eventCom);
        JIVariant evtResult = (JIVariant) (eventProcObj.get("_Class"));
        String classIdentifier = evtResult.getObjectAsString2();
        System.out.println("[Class Identifier]\t"+classIdentifier);
        JIVariant objTextAsVariant = (JIVariant) (wbemEvent.callMethodA("GetObjectText_", new Object[] {new Integer(1)}))[0];
        String asText = objTextAsVariant.getObjectAsString().getString();
        System.out.println(asText);
    }
}