docs: void putEntityManager(EntityManager entityManager) {
          if (entityManager != null && entityManager.isOpen()) {
              boolean addToPool = false;
  
              entityManager.clear();
              synchronized (this) {
                  if (ivPoolSize < ivPoolCapacity) {
                      ++ivPoolSize;
                      addToPool = true;
                  }
              }
  
              if (addToPool) {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                      Tr.debug(tc, "putEntityManager : [" + ivPoolSize + "] " +
                                   entityManager);
                  ivPool.add(entityManager);
              } else {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                      Tr.debug(tc, "putEntityManager : close : " + entityManager);
                  entityManager.close();
              }
          } else {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                  Tr.debug(tc, "putEntityManager : not open : " + entityManager);
          }
      }