protected IsisConfigurationBuilder createConfigBuilder(final ServletContext servletContext) {
final String configLocation = servletContext.getInitParameter(WebAppConstants.CONFIG_DIR_PARAM);
final ResourceStreamSourceForWebInf rssWebInf = new ResourceStreamSourceForWebInf(servletContext);
final ResourceStreamSourceContextLoaderClassPath rssContextLoaderClassPath = ResourceStreamSourceContextLoaderClassPath.create();
final ResourceStreamSourceCurrentClassClassPath rssCurrentClassPath = new ResourceStreamSourceCurrentClassClassPath();
final ResourceStreamSourceComposite compositeSource = new ResourceStreamSourceComposite(rssWebInf, rssContextLoaderClassPath, rssCurrentClassPath);
if ( configLocation != null ) {
LOG.info( "Config override location: " + configLocation );
compositeSource.addResourceStreamSource(ResourceStreamSourceFileSystem.create(configLocation));