RE: Struts+Weblogic=Problems. Changes to struts?
Thanks Matt, Does it mean that I need to modify Struts by removing support for internationalization ( removing/replacing PropertiesResourceBundle from MessageResources )? Craig, are you planning to change Struts so that it complies with Servlet 2.3 ( making all attributes Serializable )? Alex -Original Message- From: Matthew Heaton [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 07, 2000 2:14 PM To: '[EMAIL PROTECTED]' Subject: RE: Struts+Weblogic=Problems I posted my concerns on BEA's message board about Weblogic not allowing non Serialized objects to be placed inside the PageContext are two of the responses is below. I was basically told that the servlet 2.3 spec disallow non serialized objects in the PageContext so built this into the current release of Weblogic. -Matt Matt, In order for the reload-on-modify to work correctly, we have to assume that any objects that go into servlet request, servlet context and HTTP session are serializable. Otherwise, it's quite easy to get yourself into ClassCastException situation. WLS comes with reload-on-modify turned on out of the box. You can turn it off by setting reload periods to -1 (never check). There are two separate params for JSP and servlets. The one for JSPs is set in weblogic.xml descriptor, the one for servlets is set in the console. Thanks, -ruslan Matt Heaton wrote: After many unsuccessful attempts at getting Struts to work on Weblogic 5.1, I decided with give it a try on Weblogic 6.0 Beta 2 Everything seems to be deploying correct except for I get the following error (which of course breaks everything): Nov 30, 2000 1:19:37 PM PST Error HTTP [WebAppServletContext(6802820,struts-example)] Cou ld not deserialize context attribute java.io.NotSerializableException: java.util.PropertyResourceBundle at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1841) at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480) at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at weblogic.servlet.internal.AttributeWrapper.getObject(AttributeWrapper.java:7 1) at weblogic.servlet.internal.WebAppServletContext.getAttribute(WebAppServletCon text.java :207) at weblogic.servlet.jsp.PageContextImpl.getAttribute(PageContextImpl.java:164) at org.apache.struts.taglib.bean.MessageTag.doStartTag(MessageTag.java:230) at jsp_servlet._index._jspService(_index.java:105) at weblogic.servlet.jsp.JspBase.service(JspBase.java:27) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :208) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :244) at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo ntext.jav a:1107) at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java :1482) at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137) at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120) It appears that Weblogic requires any object that you use as a context attribute on a JSP page must be serializable. I went through some of the Struts source and it's trying to use objects which aren't serializable as JSP page context attributes. This looks like it may be a shortcoming in the JSP spec because it makes sense that to support to failover of sessions you would need to be able to serialize the attributes since a the attributes of a PageContext may have the scope of an entire session. -Matt -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Thursday, November 30, 2000 4:54 PM To: [EMAIL PROTECTED] Subject: Re: Struts+Weblogic=Problems but this time it looks like it's Struts Matthew Heaton wrote: The example application itself doesn't put non Serializable objects into the Http session but all throughout the struts code non Serializable objects are placed in the PageContext with a scopes of Application, Page, or Request. It appears that Weblogic 6.0 beta may be handling these as if they were placed with a Session context and disallowing non serializable objects. Whatever is going on it also appears WL is enforcing this rule in non when distributable is not set. Yep. Looking more closely at the error message, it is complaining about a non-Serializable *context* attribute, not a *session* attribute. I, like others, jumped to the wrong conclusion there. The spec provides no prohibitions on this -- only a warning that you cannot use a context attribute to share information globally in your application (the way that the example app does with its pseudo-database) in a
RE: Struts+Weblogic=Problems. Changes to struts?
They told me that the spec will disallow it but I have no idea if that is factual or not. It could just be their interpretation of the spec, from the snipets I've seen it definetly says you shouldn't put Non Serializable objects into the session but isn't very clear about putting them into the PageContext under different scopes. -Matt -Original Message- From: Punyansky, Alex [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 07, 2000 2:17 PM To: '[EMAIL PROTECTED]' Subject: RE: Struts+Weblogic=Problems. Changes to struts? Thanks Matt, Does it mean that I need to modify Struts by removing support for internationalization ( removing/replacing PropertiesResourceBundle from MessageResources )? Craig, are you planning to change Struts so that it complies with Servlet 2.3 ( making all attributes Serializable )? Alex -Original Message- From: Matthew Heaton [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 07, 2000 2:14 PM To: '[EMAIL PROTECTED]' Subject: RE: Struts+Weblogic=Problems I posted my concerns on BEA's message board about Weblogic not allowing non Serialized objects to be placed inside the PageContext are two of the responses is below. I was basically told that the servlet 2.3 spec disallow non serialized objects in the PageContext so built this into the current release of Weblogic. -Matt Matt, In order for the reload-on-modify to work correctly, we have to assume that any objects that go into servlet request, servlet context and HTTP session are serializable. Otherwise, it's quite easy to get yourself into ClassCastException situation. WLS comes with reload-on-modify turned on out of the box. You can turn it off by setting reload periods to -1 (never check). There are two separate params for JSP and servlets. The one for JSPs is set in weblogic.xml descriptor, the one for servlets is set in the console. Thanks, -ruslan Matt Heaton wrote: After many unsuccessful attempts at getting Struts to work on Weblogic 5.1, I decided with give it a try on Weblogic 6.0 Beta 2 Everything seems to be deploying correct except for I get the following error (which of course breaks everything): Nov 30, 2000 1:19:37 PM PST Error HTTP [WebAppServletContext(6802820,struts-example)] Cou ld not deserialize context attribute java.io.NotSerializableException: java.util.PropertyResourceBundle at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1841) at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480) at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at weblogic.servlet.internal.AttributeWrapper.getObject(AttributeWrapper.java:7 1) at weblogic.servlet.internal.WebAppServletContext.getAttribute(WebAppServletCon text.java :207) at weblogic.servlet.jsp.PageContextImpl.getAttribute(PageContextImpl.java:164) at org.apache.struts.taglib.bean.MessageTag.doStartTag(MessageTag.java:230) at jsp_servlet._index._jspService(_index.java:105) at weblogic.servlet.jsp.JspBase.service(JspBase.java:27) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :208) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :244) at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo ntext.jav a:1107) at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java :1482) at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137) at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120) It appears that Weblogic requires any object that you use as a context attribute on a JSP page must be serializable. I went through some of the Struts source and it's trying to use objects which aren't serializable as JSP page context attributes. This looks like it may be a shortcoming in the JSP spec because it makes sense that to support to failover of sessions you would need to be able to serialize the attributes since a the attributes of a PageContext may have the scope of an entire session. -Matt -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Thursday, November 30, 2000 4:54 PM To: [EMAIL PROTECTED] Subject: Re: Struts+Weblogic=Problems but this time it looks like it's Struts Matthew Heaton wrote: The example application itself doesn't put non Serializable objects into the Http session but all throughout the struts code non Serializable objects are placed in the PageContext with a scopes of Application, Page, or Request. It appears that Weblogic 6.0 beta may be handling these as if they were placed with a Session context and disallowing
Re: Struts+Weblogic=Problems. Changes to struts?
"Punyansky, Alex" wrote: Thanks Matt, Does it mean that I need to modify Struts by removing support for internationalization ( removing/replacing PropertiesResourceBundle from MessageResources )? Craig, are you planning to change Struts so that it complies with Servlet 2.3 ( making all attributes Serializable )? I'm afraid that I see no such requirement in the servlet 2.3 spec (and I'm on the expert group that came up with it :-). The only restrictions on Serializable attributes in the spec itself relate to *session* attributes, not *context* attributes. And that restriction only applies when you mark your app as distributable/. Note also that the WebLogic response quoted in the message from Ruslan gave an entirely different reasoning (their application server requires all attributes to be Serializable if you use the "reload on modify" feature). That's an entirely reasonable restriction for WebLogic to place, based on their container's internal architecture. It's not, however, a spec compliance issue. That all being said, I'm looking at ways to make MessageResources a Serializable object. Unfortunately, java.util.ResourceBundle (which it relies on) is *not* Serializable, so a different solution to that is going to be required. The pseudo-database in the Struts example application (which has nothing to do with the framework itself) is not Serializable, and will *not* operate correctly in a distributed environment. I'm not planning on changing that in the short term, because it's only there to give you a quick "proof of concept" that Struts is working, plus some examples of some Struts-related development techniques. Alex Craig -Original Message- From: Matthew Heaton [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 07, 2000 2:14 PM To: '[EMAIL PROTECTED]' Subject: RE: Struts+Weblogic=Problems I posted my concerns on BEA's message board about Weblogic not allowing non Serialized objects to be placed inside the PageContext are two of the responses is below. I was basically told that the servlet 2.3 spec disallow non serialized objects in the PageContext so built this into the current release of Weblogic. -Matt Matt, In order for the reload-on-modify to work correctly, we have to assume that any objects that go into servlet request, servlet context and HTTP session are serializable. Otherwise, it's quite easy to get yourself into ClassCastException situation. WLS comes with reload-on-modify turned on out of the box. You can turn it off by setting reload periods to -1 (never check). There are two separate params for JSP and servlets. The one for JSPs is set in weblogic.xml descriptor, the one for servlets is set in the console. Thanks, -ruslan Matt Heaton wrote: After many unsuccessful attempts at getting Struts to work on Weblogic 5.1, I decided with give it a try on Weblogic 6.0 Beta 2 Everything seems to be deploying correct except for I get the following error (which of course breaks everything): Nov 30, 2000 1:19:37 PM PST Error HTTP [WebAppServletContext(6802820,struts-example)] Cou ld not deserialize context attribute java.io.NotSerializableException: java.util.PropertyResourceBundle at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1841) at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480) at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at weblogic.servlet.internal.AttributeWrapper.getObject(AttributeWrapper.java:7 1) at weblogic.servlet.internal.WebAppServletContext.getAttribute(WebAppServletCon text.java :207) at weblogic.servlet.jsp.PageContextImpl.getAttribute(PageContextImpl.java:164) at org.apache.struts.taglib.bean.MessageTag.doStartTag(MessageTag.java:230) at jsp_servlet._index._jspService(_index.java:105) at weblogic.servlet.jsp.JspBase.service(JspBase.java:27) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :208) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :244) at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo ntext.jav a:1107) at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java :1482) at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137) at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120) It appears that Weblogic requires any object that you use as a context attribute on a JSP page must be serializable. I went through some of the Struts source and it's trying to use objects which aren't serializable as JSP page
Re: Struts+Weblogic=Problems. Changes to struts?
Matthew Heaton wrote: They told me that the spec will disallow it but I have no idea if that is factual or not. It could just be their interpretation of the spec, from the snipets I've seen it definetly says you shouldn't put Non Serializable objects into the session but isn't very clear about putting them into the PageContext under different scopes. Do you have an email address at WebLogic that I can follow up with? -Matt Craig
RE: Struts+Weblogic=Problems. Changes to struts?
Craig, This is a copy of the thread on weblogic.developer.interest.60beta.servlet " Re: Yet another problem with struts and Weblogic 6.0 beta " Mark Spotswood [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED]... This looks similar to an issue that came up on the JSP newsgroup recently. Below is the response I wrote there. Hope it helps. -- mark In order to support reloading of jsps/classes in a webapp, we need to create a new classloader. All stateful objects loaded from the old classloader (such as things put into the session) need to be reloaded in the new classloader. We try to preserve the state of the objects using serialization. If the object isn't serializable, you are out of luck, and the object is lost. The only other alternative in the case where we're trying to support reloading is to allow a classcastexception to occur. The only alternative in the current product is to turn off reloading, setting jsp pageCheckSecs=-1 and ServletReloadCheckSecs=-1. There is a thread on the servlet 2.3 mailing list where it looks like the servlet 2.3 spec will have words to the effect that things put into the session should be serializable if you want class reloading to work in the container. We suspect that this will be a fairly common problem, so we are trying to find ways to avoid this in our implementation such as using a classloader per jsp and handling this specific exception. Unfortunately, this will probably not make it before GA. The following is from the servlet 2.3 spec --- "In order to allow sessions to persist across class reloading within the container, it is highly advised that you should implement the Serializable interface. Otherwise, you risk the strong chance that the objects within your session will not exist after the classloader has been reloaded." I've entered CR039368 to track this issue. -- mark Matt Heaton wrote: After many unsuccessful attempts at getting Struts to work on Weblogic 5.1, I decided with give it a try on Weblogic 6.0 Beta 2 Everything seems to be deploying correct except for I get the following error (which of course breaks everything): Nov 30, 2000 1:19:37 PM PST Error HTTP [WebAppServletContext(6802820,struts-example)] Cou ld not deserialize context attribute java.io.NotSerializableException: java.util.PropertyResourceBundle at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1841) at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480) at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366) at weblogic.servlet.internal.AttributeWrapper.getObject(AttributeWrapper.java:7 1) at weblogic.servlet.internal.WebAppServletContext.getAttribute(WebAppServletCon text.java :207) at weblogic.servlet.jsp.PageContextImpl.getAttribute(PageContextImpl.java:164) at org.apache.struts.taglib.bean.MessageTag.doStartTag(MessageTag.java:230) at jsp_servlet._index._jspService(_index.java:105) at weblogic.servlet.jsp.JspBase.service(JspBase.java:27) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :208) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java :244) at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo ntext.jav a:1107) at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java :1482) at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137) at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120) It appears that Weblogic requires any object that you use as a context attribute on a JSP page must be serializable. I went through some of the Struts source and it's trying to use objects which aren't serializable as JSP page context attributes. This looks like it may be a shortcoming in the JSP spec because it makes sense that to support to failover of sessions you would need to be able to serialize the attributes since a the attributes of a PageContext may have the scope of an entire session. -Matt == -Original Message- From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] Sent: Friday, December 08, 2000 2:39 AM To: [EMAIL PROTECTED] Subject: Re: Struts+Weblogic=Problems. Changes to struts? Matthew Heaton wr
