java解析xml文件多个线程同时访问时内存溢出

     java解析xml文件多个线程同时访问时内存溢出，代码如下：

解析的xml文件大小大概2M-10M，该怎么解决呢？

String sourceFile = ConfigReader.get("data.store.path") + article.getSourceFile();
        
        org.dom4j.Document document = null;
        FileInputStream fin = null;
        try {
            fin = new FileInputStream(new File(sourceFile));
            document = new SAXReader().read(fin);
        } catch (final FileNotFoundException e) {
            final String msg = "内容单元xml文件不存在：" + sourceFile;
            log.error(msg, e);
            throw new RuntimeException(msg, e);
        } catch (final DocumentException e) {
            final String msg = "解析内容单元xml文件失败：" + sourceFile;
            log.error(msg, e);
            throw new RuntimeException(msg, e);
        } finally {
            IOUtils.closeQuietly(fin);
        }
        
        final StringBuilder xpath = new StringBuilder("/KFMP/DOCS/DOC[@GUID='")
            .append(article.getGuid()).append("']/").append("CONTENT");

        final Node node = document.selectSingleNode(xpath.toString());
        final String value = node.getText();
        article.setContent(value);
        
        final StringBuilder coordXpath = new StringBuilder("/KFMP/DOCS/DOC[@GUID='")
        .append(article.getGuid()).append("']/").append("COORDS");
        final Node coordsNode = document.selectSingleNode(coordXpath.toString());
        final String coordsValue = coordsNode.getText();
        article.setCoords(coordsValue);
        
        final StringBuilder briefXpath = new StringBuilder("/KFMP/DOCS/DOC[@GUID='")
        .append(article.getGuid()).append("']/").append("BRIEF");
        final Node briefNode = document.selectSingleNode(briefXpath.toString());
        final String briefValue = briefNode.getText();
        article.setBrief(briefValue);
        
        return article;