code: CapabilityServiceTarget getServiceTarget(final Step targetActiveStep) throws UnsupportedOperationException {
  
          readOnly = false;
  
          assert isControllingThread();
  
          if (!isRuntimeChangeAllowed()) {
              throw ControllerLogger.ROOT_LOGGER.serviceTargetRuntimeOperationsOnly();
          }
          ensureWriteLockForRuntime();
  
          final ContextServiceBuilderSupplier supplier = new ContextServiceBuilderSupplier() {
              @Override
              public <T> ContextServiceBuilder<T> getContextServiceBuilder(ServiceBuilder<T> delegate, final ServiceName name) {
  
                  final ContextServiceInstaller csi = new ContextServiceInstaller() {
  
                      @Override
                      public <X> ServiceController<X> installService(ServiceBuilder<X> realBuilder) {
                          return OperationContextImpl.this.installService(realBuilder, name, targetActiveStep);
                      }
  
                      @Override
                      public ServiceName getCapabilityServiceName(String capabilityName, Class<?> serviceType, PathAddress address) {
                          return OperationContextImpl.this.getCapabilityServiceName(capabilityName, serviceType, address);
                      }
                  };
                  return new ContextServiceBuilder<T>(delegate, csi);
              }
          };
          ServiceTarget delegate = targetActiveStep.getScopedServiceTarget(modelController.getServiceTarget());
          ContextServiceTarget cst = new ContextServiceTarget(delegate, supplier, targetActiveStep.address);
          serviceTargets.add(cst);
          return cst;
      }
docs: Gets a service target that will ensure that any
  {@link org.jboss.msc.service.ServiceTarget#addService(org.jboss.msc.service.ServiceName, org.jboss.msc.service.Service)
  added services} will be tracked for subsequent verification of service stability.
  
  @param targetActiveStep the {@link org.jboss.as.controller.AbstractOperationContext.Step} that encapsulates
  the {@link org.jboss.as.controller.OperationStepHandler} that is making the call.
  @return the service target