我目前正在一台具有以下属性的机器上开发 Java Web 应用程序：
- Ubuntu 服务器版 Linux 12.04 64 位
- Sun Java JDK 版本 7
- Apache Tomcat 7.0.30
- Netbeans IDE，版本 7.1.2
我的项目包含一个 SOAP Web 服务接口，它维护一个共享的内存对象。为了使对象对所有线程可见，我开发了一个 Singleton。我在下面发布了我的应用程序的代码：
@WebService()
public class ETL_WS {
private Singleton CAP_offer_coupon_map;
public ETL_WS() { }
/**
* This method adds a single coupon record to the memory map.
*/
@WebMethod
synchronized public int singleCouponLoad(@WebParam(name =
"CouponID") long coupon_id,
@WebParam(name = "ProductCategoryID") long product_category_id,
@WebParam(name = "DateTo") Date dateTo,
@WebParam(name = "LocationID") Location location_id) {
Coupon _c = new Coupon(coupon_id, product_category_id, dateTo);
if(location_id != null)
_c.setLocation(location_id);
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
Coupon _tmp = _data.getCoupon(coupon_id);
if(_tmp == null)
return -1;
_data.insertCoupon(_c);
return 0;
}
/**
* This method adds a single offer record to the memory map.
*/
@WebMethod
synchronized public int singleOfferLoad(@WebParam(name =
"OfferID") long offer_id,
@WebParam(name = "ProductCategoryID") long product_category_id,
@WebParam(name = "DateTo") Date dateTo,
@WebParam(name = "LocationID") Location location_id) {
Offer _o = new Offer(offer_id, product_category_id, dateTo);
if(location_id != null)
_o.setLocation(location_id);
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
Offer _tmp = _data.getOffer(offer_id);
if(_tmp == null)
return -1;
_data.insertOffer(_o);
return 0;
}
@WebMethod
synchronized public String getAllCoupons() {
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
HashMap<Long, Coupon> _c = _data.getCoupons_map();
return _c.toString();
}
@WebMethod
synchronized public String getAllOffers() {
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
HashMap<Long, Offer> _o = _data.getOffers_map();
return _o.toString();
}
@WebMethod
synchronized public long getProductIdFromCouponId(@**WebParam(name
= "CouponID") long coupon_id) {
long _product_id = -1;
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
Coupon _c = _data.getCoupon(coupon_id);
if(_c != null)
_product_id = _c.getCoupon_id();
return _product_id;
}
@WebMethod
synchronized public long getProductIdFromOfferId(@WebParam(name = "OfferID") long
offer_id) {
long _product_id = -1;
CAP_CouponOfferCollection _data = CAP_offer_coupon_map.getModel();
Offer _o = _data.getOffer(offer_id);
if(_o != null)
_product_id = _o.getOffer_id();
return _product_id;
}
}
单例包装类如下所示：
public class Singleton {
private static boolean _instanceFlag = false;
private static final Singleton _instance = new Singleton();
private static CAP_CouponOfferCollection _data;
private Singleton() {
_data = new CAP_CouponOfferCollection();
_instanceFlag = true;
}
public static synchronized CAP_CouponOfferCollection getModel() {
if(_instanceFlag == false) {
_data = new CAP_CouponOfferCollection();
_instanceFlag = true;
}
return _data;
}
}
CAP_CouponOfferCollection 类如下所示：
public class CAP_CouponOfferCollection {
private HashMap<Long, Coupon> _coupons_map;
private HashMap<Long, ArrayList<Long>> _product_to_coupons_map;
private HashMap<Long, Offer> _offers_map;
private HashMap<Long, ArrayList<Long>> _product_cat_to_offers_map;
private static long _creation_time;
public CAP_CouponOfferCollection() {
_creation_time = System.currentTimeMillis();
System.out.println("Creation of CAP_CouponOffer object: " +
_creation_time);
}
synchronized public void insertCoupon(Coupon newCoupon) {
if(_coupons_map == null) {
_coupons_map = new HashMap<Long, Coupon>();
_product_to_coupons_map =
new HashMap<Long, ArrayList<Long>>();
}
Long key = newCoupon.getCoupon_id();
if(!_coupons_map.containsKey(key)) {
_coupons_map.put(key, newCoupon);
key = newCoupon.getProductCategory_id();
if(_product_to_coupons_map.containsKey(key)) {
ArrayList<Long> _c_list = _product_to_coupons_map.get(key);
_c_list.add(newCoupon.getCoupon_id());
_product_to_coupons_map.remove(key);
_product_to_coupons_map.put(key, _c_list);
}else {
ArrayList<Long> _c_list = new ArrayList<Long>();
_c_list.add(newCoupon.getCoupon_id());
_product_to_coupons_map.put(key, _c_list);
}
}
}
synchronized public void insertOffer(Offer newOffer) {
if(_offers_map == null) {
_offers_map = new HashMap<Long, Offer>();
_product_cat_to_offers_map =
new HashMap<Long, ArrayList<Long>>();
}
Long key = newOffer.getOffer_id();
if(!_offers_map.containsKey(key)) {
_offers_map.put(key, newOffer);
key = newOffer.getProductCategory_id();
if(_product_cat_to_offers_map.containsKey(key)) {
ArrayList<Long> _o_list = _product_cat_to_offers_map.get(key);
_o_list.add(newOffer.getOffer_id());
_product_cat_to_offers_map.remove(key);
_product_cat_to_offers_map.put(key, _o_list);
}else {
ArrayList<Long> _o_list = new ArrayList<Long>();
_o_list.add(newOffer.getOffer_id());
_product_cat_to_offers_map.put(key, _o_list);
}
}
}
synchronized public void removeCoupon(long couponId) {
Coupon _c;
Long key = new Long(couponId);
if(_coupons_map != null && _coupons_map.containsKey(key)) {
_c = (Coupon) _coupons_map.get(key);
_coupons_map.remove(key);
Long product = new Long(_c.getCoupon_id());
ArrayList<Long> _c_list =
(ArrayList<Long>) _product_to_coupons_map.get(product);
_c_list.remove(key);
_product_to_coupons_map.remove(product);
_product_to_coupons_map.put(product, _c_list);
}
}
synchronized public void removeOffer(long offerId) {
Offer _o;
Long key = new Long(offerId);
if(_offers_map != null && _offers_map.containsKey(key)) {
_o = (Offer) _offers_map.get(key);
_offers_map.remove(key);
Long product = new Long(_o.getOffer_id());
ArrayList<Long> _o_list =
(ArrayList<Long>) _product_cat_to_offers_map.get(product);
_o_list.remove(key);
_product_cat_to_offers_map.remove(product);
_product_cat_to_offers_map.put(product, _o_list);
}
}
synchronized public Coupon getCoupon(long CouponID) {
Long key = new Long(CouponID);
if(_coupons_map != null && _coupons_map.containsKey(key)) {
Coupon _c = (Coupon) _coupons_map.get(key);
Date _now = new Date();
if(_now.compareTo(_c.getDateTo()) > 0) {
this.removeCoupon(CouponID);
return null;
}
return (Coupon) _coupons_map.get(key);
}else
return null;
}
synchronized public Offer getOffer(long OfferID) {
Long key = new Long(OfferID);
if(_offers_map != null && _offers_map.containsKey(key)) {
Offer _o = (Offer) _offers_map.get(key);
Date _now = new Date();
if(_now.compareTo(_o.getDateTo()) > 0) {
this.removeOffer(OfferID);
return null;
}
return (Offer) _offers_map.get(key);
}else
return null;
}
synchronized public ArrayList<Long> getCoupons(long ProductID) {
Long key = new Long(ProductID);
if(_product_to_coupons_map != null && _product_to_coupons_map.containsKey(key))
{
ArrayList<Long> _c_list =
(ArrayList<Long>) _product_to_coupons_map.get(key);
Iterator itr = _c_list.iterator();
while(itr.hasNext()) {
Long l = (Long) itr.next();
if(this.getCoupon(l.longValue()) == null)
_c_list.remove(l.intValue());
}
_product_to_coupons_map.remove(key);
_product_to_coupons_map.put(key, _c_list);
return _c_list;
}else
return null;
}
synchronized public ArrayList<Long> getOffers(long ProductID) {
Long key = new Long(ProductID);
if(_product_cat_to_offers_map != null &&
_product_cat_to_offers_map.containsKey(key)) {
ArrayList<Long> _o_list = _product_cat_to_offers_map.get(key);
Iterator itr = _o_list.iterator();
while(itr.hasNext()) {
Long l = (Long) itr.next();
if(this.getOffer(l.longValue()) == null)
_o_list.remove(l.intValue());
}
_product_cat_to_offers_map.remove(key);
_product_cat_to_offers_map.put(key, _o_list);
return _o_list;
}else
return null;
}
synchronized public HashMap<Long, Coupon> getCoupons_map() {
return _coupons_map;
}
synchronized public void setCoupons_map(HashMap<Long, Coupon> _coupons_map) {
this._coupons_map = _coupons_map;
}
synchronized public static long getCreation_time() {
return _creation_time;
}
synchronized public void cleanup_offers() {
if(_product_cat_to_offers_map != null) {
Set _offers_key_set = _product_cat_to_offers_map.keySet();
Iterator itr = _offers_key_set.iterator();
while(itr.hasNext()) {
Long l = (Long) itr.next();
this.getOffers(l.longValue());
}
}
}
synchronized public void cleanup_coupons() {
if(_product_to_coupons_map != null) {
Set _coupons_key_set = _product_to_coupons_map.keySet();
Iterator itr = _coupons_key_set.iterator();
while(itr.hasNext()) {
Long l = (Long) itr.next();
this.getCoupons(l.longValue());
}
}
}
}
问题是，当我将上述应用程序（其名称为 ETL_Procedures）部署到 Apache Tomcat 时，我得到以下 SEVERE 日志条目：
SEVERE: The web application [/ETL_Procedures] appears to have started a thread named [maintenance-task-executor-thread-1] but has failed to stop it. This is very likely to create a memory leak.
Oct 03, 2012 5:35:03 PM org.apache.catalina.loader.WebappClassLoadercheckThreadLocalMapForLeaks
SEVERE: The web application [/ETL_Procedures] created a ThreadLocal with key of type [org.glassfish.gmbal.generic.OperationTracer$1] (value [org.glassfish.gmbal.generic.OperationTracer$1@4c24821]) and a value of type [java.util.ArrayList] (value [[]]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
Oct 03, 2012 5:35:03 PM org.apache.catalina.loader.WebappClassLoadercheckThreadLocalMapForLeaks
SEVERE: The web application [/ETL_Procedures] created a ThreadLocal with key of type [com.sun.xml.bind.v2.ClassFactory$1] (value [com.sun.xml.bind.v2.ClassFactory$1@6f0d70f7]) and a value of type [java.util.WeakHashMap] (value [{class com.sun.xml.ws.runtime.config.TubeFactoryList=java.lang.ref.WeakReference@5b73a116, class javax.xml.bind.annotation.adapters.CollapsedStringAdapter=java.lang.ref.WeakReference@454da42, class com.sun.xml.ws.runtime.config.MetroConfig=java.lang.ref.WeakReference@5ec52546, class com.sun.xml.ws.runtime.config.TubeFactoryConfig=java.lang.ref.WeakReference@61124745, class java.util.ArrayList=java.lang.ref.WeakReference@770534cc, class com.sun.xml.ws.runtime.config.Tubelines=java.lang.ref.WeakReference@76cd7a1f, class javax.xml.bind.annotation.W3CDomHandler=java.lang.ref.WeakReference@2c0cc628, class com.sun.xml.ws.runtime.config.TubelineDefinition=java.lang.ref.WeakReference@7aa582af}]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
Oct 03, 2012 5:35:03 PM org.apache.catalina.loader.WebappClassLoadercheckThreadLocalMapForLeaks
SEVERE: The web application [/ETL_Procedures] created a ThreadLocal with key of type [com.sun.xml.bind.v2.runtime.Coordinator$1] (value [com.sun.xml.bind.v2.runtime.Coordinator$1@826ee11]) and a value of type [java.lang.Object[]] (value [[Ljava.lang.Object;@33d7a245]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
Oct 03, 2012 5:35:03 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/ETL_Procedures] created a ThreadLocal with key of type [org.glassfish.gmbal.generic.OperationTracer$1] (value [org.glassfish.gmbal.generic.OperationTracer$1@4c24821]) and a value of type [java.util.ArrayList] (value [[]]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
我真的不知道是什么导致了这些内存泄漏。我的问题如下：
- 谁能怀疑我的网络服务可能有什么问题？如果内存泄漏的原因是 Singleton 对象，我还能做些什么来满足我的应用程序要求并避免内存泄漏。
- 有什么工具可以用来监控我的线程，究竟是什么导致了这些 SEVERE 消息？
如果我让我的应用程序部署了很长时间，我会收到带有以下消息的 IllegalStateException：
INFO: Illegal access: this web application instance has been stopped already. Could not load com.sun.xml.ws.rx.rm.localization.LocalizationMessages. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact. java.lang.IllegalStateException at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1600) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559) at com.sun.xml.ws.rx.rm.runtime.sequence.SequenceMaintenanceTask.run(SequenceMaintenanceTask.java:81) at com.sun.xml.ws.commons.DelayedTaskManager$Worker.run(DelayedTaskManager.java:91) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:722)
如何查看导致此异常的整个调用路径？
感谢您的宝贵时间，对于这么长的信息，我感到非常抱歉。