public File downloadJar(DistributedMember locator, String groupName, String jarName)
      throws IOException {
    ClusterConfigurationLoader loader = new ClusterConfigurationLoader();
    return loader.downloadJar(locator, groupName, jarName);
  }
Retrieve a deployed jar from a locator. The retrieved file is staged in a temporary location.

@param locator the DistributedMember
@param groupName the group to use when retrieving the jar
@param jarName the name of the deployed jar
@return a File referencing the downloaded jar. The File is downloaded to a temporary location.
geode-core/src/main/java/org/apache/geode/distributed/internal/InternalConfigurationPersistenceService.java