Set up your environment for debugging and the ability to see the source code. Follow https://rsjazz.wordpress.com/2015/09/30/learning-to-fly-getting-started-with-the-rtc-java-apis/ to do that. Also see https://rsjazz.wordpress.com/2013/09/24/managing-workspaces-streams-and-components-using-the-plain-java-client-libraries/


To get the component from a workspace/stream use IWorkspaceConnection.getComponents()

    public IWorkspaceHandle getStreamHandleByName(String projectName,String streamName ) throws TeamRepositoryException {
        IWorkspaceManager wm = SCMPlatform.getWorkspaceManager(repo);
        IWorkspaceHandle stream = null;
        boolean not_found = true;
       
        // Check stream name       
        if (streamName == null) {
            throw new TeamRepositoryException("Stream Name required");           
        }

        // Create search criteria
        IWorkspaceSearchCriteria crit = IWorkspaceSearchCriteria.FACTORY.newInstance();
        crit.setExactName(streamName);
        crit.setExactOwnerName(projectName);
        crit.setKind(IWorkspaceSearchCriteria.STREAMS);
        List streams = wm.findWorkspaces(crit, 1, MONITOR);
        Iterator it = streams.iterator();
        if (!(it.hasNext())) {
           
            // Check if stream is owned by a team
            IProjectArea project = getProjectByName(projectName);
            List teamAreas = project.getTeamAreas();
            Iterator itt = teamAreas.iterator();
            while (not_found && itt.hasNext()) {           
                ITeamAreaHandle teamAreaHandle = (ITeamAreaHandle) itt.next();       
                ITeamArea teamArea = (ITeamArea)repo.itemManager().fetchCompleteItem((ITeamAreaHandle)teamAreaHandle, IItemManager.DEFAULT, MONITOR);
                String teamName = teamArea.getName();
               
                // Create search Criteria
                crit.setExactOwnerName(teamName);
           
                streams = wm.findWorkspaces(crit, Integer.MAX_VALUE, MONITOR);
                for (it = streams.iterator(); it.hasNext();) {
                    stream = (IWorkspaceHandle) it.next();
                    not_found = false;
                }
            }
        } else {
            // Load stream handle
            stream = (IWorkspaceHandle) it.next();
            not_found = false;
        }
        if (not_found) {
            throw new TeamRepositoryException("Could not find Stream " + streamName);           
        }
       
        return stream;
    }




       // to get components in a stream

        IWorkspaceManager wm = SCMPlatform.getWorkspaceManager(repo);
        IWorkspaceHandle streamHandle = getStreamHandleByName(projectName,streamName);
        IWorkspaceConnection stream = wm.getWorkspaceConnection(streamHandle, null);

        // Get component Handle
        List components = stream.getComponents();
        List comps = new ArrayList();
        for (Iterator a = components.iterator(); a.hasNext();) {
            IComponentHandle compHandle = (IComponentHandle) a.next();
            IComponent comp = (IComponent)repo.itemManager().fetchCompleteItem(compHandle, IItemManager.DEFAULT, MONITOR);
}

this will find a file in a component, you can probaly mod it to give all files

    @SuppressWarnings("unchecked")
    public IVersionableHandle findfile(IFolderHandle root,IConfiguration iconfig,String fileName)
                                                     throws TeamRepositoryException {       
        String fileNamePath[] = {fileName};
        IVersionableHandle filePathHandle = null;
       
        // Check if file at this folder level
        filePathHandle = iconfig.resolvePath(root,fileNamePath, MONITOR);
        if (filePathHandle != null) {
            return filePathHandle;
        }                   

        // Check this file sub folders
        Map<String, IVersionableHandle> childEntries = iconfig.childEntries(root,MONITOR);
        for(Map.Entry<String, IVersionableHandle> next : childEntries.entrySet()) {
            IVersionableHandle nextVersionable = next.getValue();
            if (nextVersionable instanceof IFolderHandle) {
                filePathHandle = findfile((IFolderHandle) nextVersionable,iconfig,fileName);
               
                if (filePathHandle != null) {
                    break;
                }
            }
        }       
        return filePathHandle;
    }




            // Get component root folder
           IWorkspaceConnection stream = null;
            IConfiguration iconfig = (IConfiguration) stream.configuration(component);        
            IFolderHandle root = iconfig.rootFolderHandle(MONITOR);       
IVersionableHandle filePathHandle = findfile(root,iconfig,fileName)