How to get service resource resolver

1) Create Util class and write this re-usabled method in it, and call it where ever required.

2) Create service and service user and configurations in 

    OSGI config: Apache Sling Service User Mapper Service

    Field: Service Mappings

        Value format: <unique-package-name>:<service-name>=<service-user-name>

3) User this service name to get service resource resolver

public static ResourceResolver getServiceResolver() throws LoginException {
    Map<String, Object> param = new HashMap<>();
    param.put(ResourceResolverFactory.SUBSERVICE, "my-custom-service");
    BundleContext bundleContext = FrameworkUtil.getBundle(MyUtils.class).getBundleContext();
    ServiceReference resourceResolverFactoryRef = bundleContext
    .getServiceReference(ResourceResolverFactory.class.getName());
    ResourceResolverFactory resFactory = (ResourceResolverFactory) bundleContext
    .getService(resourceResolverFactoryRef);
    return resFactory.getServiceResourceResolver(param);}