垃圾收集在java中似乎不起作用

Question

下面的方法有2个for循环。Firstloop迭代36000次，inner forloop迭代24次，因此记录插入的总数将为864000。代码执行运行了将近3.5小时并终止。（记录插入失败）只有在outer for循环结束后才会关闭会话并提交事务。发现执行过程中RAM消耗近6.9GB

@SuppressWarnings("unchecked")


public void createBRResults() {

    List<BusinessRules> businessRuleList = null;
    Organization organization = null;
    Brresults brresults = null;
    Criteria criteria = null;
    Criteria newCriteria = null;
    String brStatus = "Live";
    Date date = new Date();
    Session session = sessionFactory.openSession();
    Transaction transaction = null;
    try {
        if (callInfos == null) {
            callInfos = getEntities(CallInfo.class);
        }
        for (CallInfo callInfo : callInfos) {
            transaction = session.beginTransaction();
            criteria = session.createCriteria(BusinessRules.class);
            criteria.createCriteria("businessGoals").add(
                    Restrictions.eq("category", callInfo.getCategory()));
            businessRuleList = criteria.list();
            organization = callInfo.getOrganization();
            for (BusinessRules businessRule : businessRuleList) {
                brresults = new Brresults();
                brresults.setBusinessRule(businessRule);
                brresults.setCallInfo(callInfo);
                brresults.setCreatedDate(date);
                brresults.setModifiedDate(date);
                brresults.setOrganization(organization);
                brresults.setBrrStatus(brStatus);
                brresults.setBrrValue(Math.random() < 0.5 ? 0 : 1);
                session.save(brresults);
                brresults = null;
            }
            criteria = null;
            organization = null;
            businessRuleList = null;
            session.flush();
            session.clear();
            transaction.commit();
            System.gc();
        }
    } catch (Exception ex) {
        ex.printStackTrace();
    } finally {
        session.close();
    }
}

我已经附上了最后几行GC日志来指示内存分配

堆PSYoungGen总计1862144K，已使用889367K[0x0000000715D80000,0x00000007BDC80000,0x00000007C0000000)

eden空间979968K,90%使用[0x0000000715D80000,0x000000074C205E48,0x0000000751A80000)从空间882176K,0%使用[0x0000000787F00000,0x0000000787F00000,0x00000007BDC80000)到空间885760K,0%使用[0x0000000751A80000,0x0000000751A80000,0x0000000787B80000)ParOldGen总计5576192K,使用5576027K[0x00000005C1800000,0x00000007B80000

但如果我关闭会话并每隔24次重复再次打开会话，则记录插入成功，所需时间为55分钟。但RAM利用率约为3GB。

为什么垃圾收集不能正常进行？代码中有哪些bug？

Answer 1

session正在累积对您所接触的所有对象的引用，因为如果您在同一会话中两次请求该对象，它必须返回完全相同的对象。您需要定期关闭它以允许它丢弃其上下文。