code: public P2SVpnServerConfigurationInner createOrUpdate(String resourceGroupName, String virtualWanName, String p2SVpnServerConfigurationName, P2SVpnServerConfigurationInner p2SVpnServerConfigurationParameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, virtualWanName, p2SVpnServerConfigurationName, p2SVpnServerConfigurationParameters).toBlocking().last().body();
      }
docs: Creates a P2SVpnServerConfiguration to associate with a VirtualWan if it doesn't exist else updates the existing P2SVpnServerConfiguration.
  
  @param resourceGroupName The resource group name of the VirtualWan.
  @param virtualWanName The name of the VirtualWan.
  @param p2SVpnServerConfigurationName The name of the P2SVpnServerConfiguration.
  @param p2SVpnServerConfigurationParameters Parameters supplied to create or Update a P2SVpnServerConfiguration.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws ErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the P2SVpnServerConfigurationInner object if successful.