docs: public ConnectionManager getConnectionManager() {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(this, tc, "Connection manager is " + cm + " for managed connection " + this);
              if (cm == null && pm != null) {
                  Tr.debug(this, tc, "Connection pool is " + this.pm.toString());
              }
          }
          if (cm != null) {
              return cm;
          } else {
              IllegalStateException e = new IllegalStateException("ConnectionManager is null");
              Tr.error(tc, "ILLEGAL_STATE_EXCEPTION_J2CA0079", "getConnectionManager", e);
              throw e;
          }
      }