code: private List<String> getIds(ConfigurationAdmin ca, String[] pids) {
          final String methodName = "getIds(): ";
          if (pids == null) {
              return Collections.emptyList();
          }
          List<String> ids = new ArrayList<String>();
          for (String pid : pids) {
              try {
                  String filter = "(" + org.osgi.framework.Constants.SERVICE_PID + "=" + pid + ")";
                  Configuration[] config = ca.listConfigurations(filter);
                  if (config == null) {
                      if (tc.isDebugEnabled())
                          Tr.debug(tc, methodName + "Configuration not found for pid " + pid);
                  } else {
                      if (tc.isDebugEnabled())
                          Tr.debug(tc, methodName + "Found config for " + pid);
                      String id = (String) config[0].getProperties().get("id");
                      ids.add(id);
                  }
              } catch (IOException e) {
                  if (tc.isDebugEnabled())
                      Tr.debug(tc, methodName + "Configuration not found for " + pid, e);
              } catch (InvalidSyntaxException e) {
                  if (tc.isDebugEnabled())
                      Tr.debug(tc, methodName + "Configuration not found for " + pid, e);
              }
          }
          return Collections.unmodifiableList(ids);
      }
docs: Find the PID in the configAdmin and get the id corresponding to it.