You could register a ServletContextListener (in web.xml) that calls some cleanup code on your singleton when the web-app is destroyed. But I don't know how this would affect your other threads, as a new ClassLoader is created when Axis is reloaded (this is why you get "another" singleton). If your singleton threw an exception if a method was called after the context had been destroyed, at least you would know what was happening.
Keith -----Original Message----- From: Donald Gorgonzola [mailto:[EMAIL PROTECTED] Sent: 21 July 2004 19:39 To: [EMAIL PROTECTED] Subject: What happens to Java objects when Axis is reloaded by Tomcat? >From a web service call I access a singleton, so subsequent web service calls can access the same object. Things work fine until Axis is reloaded (by Tomcat web app manager). I can no longer get a handle on the original singleton, instead a new singleton is created. I wouldn't mind this behavior if the original singleton was cleaned up, but instead it sticks around. I know this because I have threads that are still able to see the original singleton. So what I end up with is multiple singletons, one for every time Axis is reloaded and no way of getting a handle on the old singletons. The only way I can get rid of them is to restart Tomcat. What happens when Axis is reloaded by Tomcat? Is there any way to have the singleton objects and threads that were associated with Axis before the reload get cleaned up? Or a way to get a handle on these old objects? I am using Axis 1.1 with Tomcat 5.0.25 and Java 1.4.2. Here is some code that calls a web service that accesses a singleton. /* * SingletonTest.jws * Tests accessing a singleton from a web service call. */ public class SingletonTest { /** Shows the current value of the singleton and updates with the new value. */ public String showAndSet (String newValue) { String originalValue = Singleton.getInstance().getValue(); Singleton.getInstance().setValue(newValue); return (originalValue); } } /** Singleton.java */ public class Singleton { private static Singleton singleton = null; private String value = "unset"; /** Singleton so constructor is private. */ private Singleton() { } public static Singleton getInstance() { if (singleton == null) { singleton = new Singleton(); } return (singleton); } public String getValue() { return (value); } public void setValue (String newValue) { value = newValue; } } /* * SingletonTestClient.java * Test client used to test SingletonTest.jws. */ import org.apache.axis.client.Call; import org.apache.axis.client.Service; import org.apache.axis.encoding.XMLType; import javax.xml.rpc.ParameterMode; public class SingletonTestClient { public static void main(String [] args) throws Exception { String endpoint = "http://localhost:8080/axis/SingletonTest.jws";; if (args == null || args.length < 1) { System.err.println("Usage: SingletonTestClient <name>"); return; } String value = args[0]; String retStr = null; Object [] objs = null; Service service = new Service(); Call call = (Call) service.createCall(); call.addParameter ("showAndSet", XMLType.XSD_STRING, ParameterMode.IN ); objs = new Object [] { value }; call.setTargetEndpointAddress( new java.net.URL(endpoint) ); call.setOperationName("showAndSet"); call.setReturnType(XMLType.XSD_STRING); retStr = (String) call.invoke(objs); System.out.println("Result: " + retStr); } } _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
