Model cannot be correctly instantiated by the Use API on Prod and stage intermittently

[Amsalek4]

Hi Team,

In cloud, We are facing the below issue recently on prod and stage alone intermittently. Its showing Identifier com.allb2bsites.core.models.PageHeadModel cannot be correctly instantiated by the Use API

Its working on dev and local perfectly. we haven't done any code change on this model class recently. 

This model has been calling in page component so none of the pages are  loading and giving internal server error. I am seeing some other model class also throwing this error in xf .  We couldn't find anything apart from this error from logs. Java :11 , Both author and publisher

Model Code:

@Model(adaptables = {SlingHttpServletRequest.class}, adapters = PageHeadModel.class, defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL)
public class PageHeadModelImpl implements PageHeadModel {


    private final Logger log = LoggerFactory.getLogger(PageHeadModelImpl.class);
    private Map<String, String> languages;

    @ScriptVariable
    private Page currentPage;

    @OSGiService
    private customservice customservice;

    @OSGiService
    private Externalizer externalizer;

    @SlingObject
    private ResourceResolver resourceResolver;

    @Self
    private SlingHttpServletRequest slingRequest;

Another  model which gave this issue:

Model(adaptables = { SlingHttpServletRequest.class },
adapters =  SimpleNavModel.class,  resourceType = {SimpleNavModelImpl.RESOURCE_TYPE},
defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL)
public  class SimpleNavModelImpl implements SimpleNavModel {

protected static final String RESOURCE_TYPE = "xxxx/components/content/simple-nav/v1/simple-nav";

    @ChildResource
    private List<SimpleNavItemModel> simpleNavItems;

    @Override
    public List<SimpleNavItemModel> getSimpleNavItems() {
        if(simpleNavItems != null) {
            return new ArrayList<>(simpleNavItems);
        }
        return new ArrayList<>();
    }
}

15.05.2024 14:47:04.283 [cm-p103058-e972759-aem-publish-85c697b46b-mc865] *ERROR* [[::1] [1715784414341] GET /content/businesstravel/pt/hotel-subscription-cards/all-plus-voyageur.html HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Uncaught SlingException
org.apache.sling.scripting.sightly.SightlyException: Identifier com.allb2bsites.core.models.PageHeadModel cannot be correctly instantiated by the Use API
at org.apache.sling.scripting.sightly.impl.engine.extension.use.UseRuntimeExtension.call(UseRuntimeExtension.java:76) [org.apache.sling.scripting.sightly:1.4.20.140]
at org.apache.sling.scripting.sightly.impl.engine.runtime.RenderContextImpl.call(RenderContextImpl.java:72) [org.apache.sling.scripting.sightly:1.4.20.140]
at org.apache.sling.scripting.sightly.apps.allbbsites.components.structure.page.page__002e__html.render(page__002e__html.java:53)
at org.apache.sling.scripting.sightly.render.RenderUnit.render(RenderUnit.java:53) [org.apache.sling.scripting.sightly.runtime:1.2.6.140]
at org.apache.sling.scripting.sightly.impl.engine.SightlyCompiledScript.eval(SightlyCompiledScript.java:61) [org.apache.sling.scripting.sightly:1.4.20.140]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.call(DefaultSlingScript.java:393) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.eval(DefaultSlingScript.java:191) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.service(DefaultSlingScript.java:500) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.engine.impl.request.RequestData.service(RequestData.java:545) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.SlingComponentFilterChain.render(SlingComponentFilterChain.java:45) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:88) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.ResponseCacheFilter.doFilter(ResponseCacheFilter.java:119) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.ResponseCacheFilter.doFilter(ResponseCacheFilter.java:119) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMDebugFilter.doFilter(WCMDebugFilter.java:138) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.dynamicinclude.IncludeTagFilter.doFilter(IncludeTagFilter.java:71) [org.apache.sling.dynamic-include:3.1.2]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.acs.commons.granite.ui.components.impl.include.IncludeDecoratorFilterImpl.doFilter(IncludeDecoratorFilterImpl.java:92) [com.adobe.acs.acs-aem-commons-bundle:5.3.4]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.uriprovider.dba.DBAHeaderFilter.doFilter(DBAHeaderFilter.java:107) [com.adobe.granite.uriprovider.dba:0.2.8]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.cq.dam.cfm.ui.impl.EditorCacheFilter.doFilter(EditorCacheFilter.java:102) [com.adobe.dam.cq-dam-cfm-impl:0.12.360]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.metrics.knownerrors.impl.ErrorLoggingComponentFilter.doFilter(ErrorLoggingComponentFilter.java:71) [com.adobe.granite.metrics.knownerrors:0.0.24]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.monitoring.PageComponentRequestFilter.doFilter(PageComponentRequestFilter.java:105) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMComponentFilter.doFilter(WCMComponentFilter.java:278) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.page.PageLockFilter.doFilter(PageLockFilter.java:91) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.personalization.impl.TargetComponentFilter.doFilter(TargetComponentFilter.java:94) [com.day.cq.cq-personalization:5.13.58]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.csrf.impl.CSRFFilter.doFilter(CSRFFilter.java:225) [com.adobe.granite.csrf:1.0.26]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.SlingRequestProcessorImpl.processComponent(SlingRequestProcessorImpl.java:367) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.SlingRequestProcessorImpl.dispatchRequest(SlingRequestProcessorImpl.java:416) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.request.SlingRequestDispatcher.dispatch(SlingRequestDispatcher.java:203) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.request.SlingRequestDispatcher.include(SlingRequestDispatcher.java:102) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMComponentFilter$ForwardRequestDispatcher.include(WCMComponentFilter.java:516) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.jsp.libs.cq.Page.Page__002e__jsp._jspService(Page__002e__jsp.java:117)
at org.apache.sling.scripting.jsp.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) [org.apache.sling.scripting.jsp:2.6.0]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) [org.apache.felix.http.servlet-api:1.2.0]
at org.apache.sling.scripting.jsp.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:521) [org.apache.sling.scripting.jsp:2.6.0]
at org.apache.sling.scripting.jsp.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:464) [org.apache.sling.scripting.jsp:2.6.0]
at org.apache.sling.scripting.jsp.JspScriptEngineFactory$JspScriptEngine.callJsp(JspScriptEngineFactory.java:500) [org.apache.sling.scripting.jsp:2.6.0]
at org.apache.sling.scripting.jsp.JspScriptEngineFactory$JspScriptEngine.eval(JspScriptEngineFactory.java:582) [org.apache.sling.scripting.jsp:2.6.0]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.call(DefaultSlingScript.java:395) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.eval(DefaultSlingScript.java:191) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.scripting.core.impl.DefaultSlingScript.service(DefaultSlingScript.java:500) [org.apache.sling.scripting.core:2.4.8]
at org.apache.sling.engine.impl.request.RequestData.service(RequestData.java:545) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.SlingComponentFilterChain.render(SlingComponentFilterChain.java:45) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:88) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMDebugFilter.doFilter(WCMDebugFilter.java:138) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.cq.dam.cfm.ui.impl.EditorCacheFilter.doFilter(EditorCacheFilter.java:102) [com.adobe.dam.cq-dam-cfm-impl:0.12.360]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.metrics.knownerrors.impl.ErrorLoggingComponentFilter.doFilter(ErrorLoggingComponentFilter.java:71) [com.adobe.granite.metrics.knownerrors:0.0.24]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.monitoring.PageComponentRequestFilter.doFilter(PageComponentRequestFilter.java:105) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMComponentFilter.filterRootInclude(WCMComponentFilter.java:375) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at com.day.cq.wcm.core.impl.WCMComponentFilter.doFilter(WCMComponentFilter.java:190) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.page.PageLockFilter.doFilter(PageLockFilter.java:91) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.personalization.impl.TargetComponentFilter.doFilter(TargetComponentFilter.java:94) [com.day.cq.cq-personalization:5.13.58]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.SlingRequestProcessorImpl.processComponent(SlingRequestProcessorImpl.java:367) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.RequestSlingFilterChain.render(RequestSlingFilterChain.java:49) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:88) [org.apache.sling.engine:2.15.10]
at org.apache.sling.dynamicinclude.SyntheticResourceFilter.doFilter(SyntheticResourceFilter.java:66) [org.apache.sling.dynamic-include:3.1.2]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.dam.core.impl.assetlinkshare.AdhocAssetShareAuthHandler.doFilter(AdhocAssetShareAuthHandler.java:516) [com.day.cq.dam.cq-dam-core:5.15.104]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.day.cq.dam.core.impl.servlet.ActivityRecordHandler.doFilter(ActivityRecordHandler.java:141) [com.day.cq.dam.cq-dam-core:5.15.104]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.requests.logging.impl.RequestLoggerImpl.doFilter(RequestLoggerImpl.java:135) [com.adobe.granite.requests.logging:1.0.22]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.rest.impl.servlet.ApiResourceFilter.doFilter(ApiResourceFilter.java:70) [com.adobe.granite.rest.api:1.1.42]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.rest.assets.impl.AssetContentDispositionFilter.doFilter(AssetContentDispositionFilter.java:96) [com.adobe.granite.rest.assets:1.0.74]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.AuthoringUIModeServiceImpl.doFilter(AuthoringUIModeServiceImpl.java:385) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.ResponseCacheFilter.doFilter(ResponseCacheFilter.java:119) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.ResponseCacheFilter.doFilter(ResponseCacheFilter.java:119) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.mobile.core.impl.redirect.RedirectFilter.doFilter(RedirectFilter.java:248) [com.day.cq.wcm.cq-wcm-mobile-core:5.11.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.allb2bsites.core.filters.LoggingFilter.doFilter(LoggingFilter.java:58) [aem-allb2bsites-project.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.PageRedirectFilter.doFilter(PageRedirectFilter.java:74) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.NotFoundPageFilter.doFilter(NotFoundPageFilter.java:67) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.dynamicinclude.CacheControlFilter.doFilter(CacheControlFilter.java:67) [org.apache.sling.dynamic-include:3.1.2]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.PageRedirectFilter.doFilter(PageRedirectFilter.java:74) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.NotFoundPageFilter.doFilter(NotFoundPageFilter.java:67) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.uriprovider.dba.DBAHeaderFilter.doFilter(DBAHeaderFilter.java:107) [com.adobe.granite.uriprovider.dba:0.2.8]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.cq.wcm.core.extensions.amp.internal.AmpModeForwardFilter.doFilter(AmpModeForwardFilter.java:95) [com.adobe.cq.core.wcm.components.extensions.amp:2.24.6]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.cq.wcm.core.components.internal.servlets.TableOfContentsFilter.doFilter(TableOfContentsFilter.java:122) [com.adobe.cq.core.wcm.components.core:2.24.6]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.dam.core.impl.servlet.DisableLegacyServletFilter.executeFilter(DisableLegacyServletFilter.java:197) [com.day.cq.dam.cq-dam-core:5.15.104]
at com.day.cq.dam.core.impl.servlet.DisableLegacyServletFilter.doFilter(DisableLegacyServletFilter.java:154) [com.day.cq.dam.cq-dam-core:5.15.104]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.debug.RequestProgressTrackerLogFilter.doFilter(RequestProgressTrackerLogFilter.java:109) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.POSContextFilter.doFilter(POSContextFilter.java:168) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.filters.POSContextFilter.doFilter(POSContextFilter.java:168) [acelibrary.core:2024.515.1125921.0004142516]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.ace.core.pdp.filters.PDPAuthorModeFilter.doFilter(PDPAuthorModeFilter.java:117)
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.ace.core.pdp.filters.PDPAuthorModeFilter.doFilter(PDPAuthorModeFilter.java:117)
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.foundation.forms.FormsHandlingServletHelper.handleFilter(FormsHandlingServletHelper.java:226) [com.day.cq.wcm.cq-wcm-foundation:5.14.46]
at com.day.cq.wcm.foundation.forms.impl.FormsHandlingServlet.doFilter(FormsHandlingServlet.java:138) [com.day.cq.wcm.cq-wcm-foundation:5.14.46]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.optout.impl.OptOutFilter.doFilter(OptOutFilter.java:76) [com.adobe.granite.optout:1.0.0]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.foundation.forms.FormsHandlingServletHelper.handleFilter(FormsHandlingServletHelper.java:226) [com.day.cq.wcm.cq-wcm-foundation:5.14.46]
at com.adobe.cq.wcm.core.components.internal.servlets.CoreFormHandlingServlet.doFilter(CoreFormHandlingServlet.java:123) [com.adobe.cq.core.wcm.components.core:2.24.6]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.acs.commons.wcm.impl.AemEnvironmentIndicatorFilter$InnerEnvironmentIndicatorFilter.doFilter(AemEnvironmentIndicatorFilter.java:467) [com.adobe.acs.acs-aem-commons-bundle:5.3.4]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.day.cq.wcm.core.impl.WCMRequestFilter.doFilter(WCMRequestFilter.java:90) [com.day.cq.wcm.cq-wcm-core:5.14.150]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.rewriter.impl.RewriterFilter.doFilter(RewriterFilter.java:87) [org.apache.sling.rewriter:1.3.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.httpcache.impl.InnerCacheFilter.doFilter(InnerCacheFilter.java:81) [com.adobe.granite.httpcache.core:1.0.8]
at com.adobe.granite.httpcache.impl.InnerCacheFilter.doFilter(InnerCacheFilter.java:60) [com.adobe.granite.httpcache.core:1.0.8]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.i18n.impl.I18NFilter.doFilter(I18NFilter.java:131) [org.apache.sling.i18n:2.6.2]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.csrf.impl.CSRFFilter.doFilter(CSRFFilter.java:225) [com.adobe.granite.csrf:1.0.26]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.security.impl.ContentDispositionFilter.doFilter(ContentDispositionFilter.java:162) [org.apache.sling.security:1.2.0]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:84) [org.apache.sling.engine:2.15.10]
at com.adobe.granite.resourceresolverhelper.impl.ResourceResolverHelperImpl.doFilter(ResourceResolverHelperImpl.java:79) [com.adobe.granite.resourceresolverhelper:1.0.6]
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:78) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.SlingRequestProcessorImpl.doProcessRequest(SlingRequestProcessorImpl.java:240) [org.apache.sling.engine:2.15.10]
at org.apache.sling.engine.impl.SlingMainServlet.service(SlingMainServlet.java:130) [org.apache.sling.engine:2.15.10]
at org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:127) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:86) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.acs.commons.wcm.impl.AemEnvironmentIndicatorFilter.doFilter(AemEnvironmentIndicatorFilter.java:218) [com.adobe.acs.acs-aem-commons-bundle:5.3.4]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.metrics.redimpl.REDMetricsServletFilter.doFilter(REDMetricsServletFilter.java:214) [com.adobe.granite.metrics.red:1.2.0]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.metrics.knownerrors.impl.ReportingRequestFilter.doFilter(ReportingRequestFilter.java:100) [com.adobe.granite.metrics.knownerrors:0.0.24]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.cors.impl.CORSFilter.doFilter(CORSFilter.java:94) [com.adobe.granite.cors:1.0.22]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.license.impl.http.LicenseCheckFilter.doFilter(LicenseCheckFilter.java:301) [com.adobe.granite.license.http:1.0.0]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.i18n.impl.I18NFilter.doFilter(I18NFilter.java:131) [org.apache.sling.i18n:2.6.2]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.featureflags.impl.FeatureManager.doFilter(FeatureManager.java:116) [org.apache.sling.featureflags:1.2.2]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.engine.impl.log.RequestLoggerFilter.doFilter(RequestLoggerFilter.java:73) [org.apache.sling.engine:2.15.10]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.engine.impl.parameters.RequestParameterSupportConfigurer.doFilter(RequestParameterSupportConfigurer.java:67) [org.apache.sling.engine:2.15.10]
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:149) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.InvocationChain.doFilter(InvocationChain.java:81) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.Dispatcher$1.doFilter(Dispatcher.java:152) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:992) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.ratelimit.AdaptiveRateLimitFilter.handleRequest(AdaptiveRateLimitFilter.java:465) [com.adobe.granite.ratelimit:5.0.4]
at com.adobe.granite.ratelimit.AdaptiveRateLimitFilter.doFilter(AdaptiveRateLimitFilter.java:407) [com.adobe.granite.ratelimit:5.0.4]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.auth.oauth.impl.OAuthCallbackFilter.doFilter(OAuthCallbackFilter.java:78) [com.adobe.granite.auth.oauth:1.10.30]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.auth.ims.impl.IMSClusterExchangeTokenPreprocessor.doFilter(IMSClusterExchangeTokenPreprocessor.java:241) [com.adobe.granite.auth.ims:1.4.54]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.cors.impl.CORSFilter.doFilter(CORSFilter.java:94) [com.adobe.granite.cors:1.0.22]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.security.impl.ReferrerFilter.doFilter(ReferrerFilter.java:345) [org.apache.sling.security:1.2.0]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.sslfilter.internal.SslFilter.doFilter(SslFilter.java:97) [org.apache.felix.http.sslfilter:1.2.6]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at org.apache.sling.engine.impl.log.RequestLoggerPreprocessor.doFilter(RequestLoggerPreprocessor.java:47) [org.apache.sling.engine:2.15.10]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at com.adobe.granite.probes.impl.ProbesPreprocessor.doFilter(ProbesPreprocessor.java:54) [com.adobe.granite.probes:1.0.16]
at org.apache.felix.http.base.internal.handler.PreprocessorHandler.handle(PreprocessorHandler.java:137) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager$2.doFilter(WhiteboardManager.java:998) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.whiteboard.WhiteboardManager.invokePreprocessors(WhiteboardManager.java:1002) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:94) [org.apache.felix.http.jetty:4.2.26]
at org.apache.felix.http.base.internal.dispatch.DispatcherServlet.service(DispatcherServlet.java:49) [org.apache.felix.http.jetty:4.2.26]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) [org.apache.felix.http.servlet-api:1.2.0]
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:554) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:191) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:181) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.Server.handle(Server.java:516) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883) [org.apache.felix.http.jetty:4.2.26]
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034) [org.apache.felix.http.jetty:4.2.26]
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.IllegalArgumentException: com.allb2bsites.core.models.PageHeadModel represents an interface or an abstract class which cannot be instantiated.
at org.apache.sling.scripting.sightly.impl.engine.extension.use.JavaUseProvider.loadObject(JavaUseProvider.java:215) [org.apache.sling.scripting.sightly:1.4.20.140]
at org.apache.sling.scripting.sightly.impl.engine.extension.use.JavaUseProvider.provide(JavaUseProvider.java:130) [org.apache.sling.scripting.sightly:1.4.20.140]
at org.apache.sling.scripting.sightly.impl.engine.extension.use.UseRuntimeExtension.call(UseRuntimeExtension.java:71) [org.apache.sling.scripting.sightly:1.4.20.140]
... 257 common frames omitted

@Kamal_Kishor @Mahesh_Gunaje  @sarav_prakash @arunpatidar @VeenaVikraman @Vijayalakshmi_S 

[sarav_prakash]

Hi @Amsalek4 I dont have an exact answer. But is weird, your issue is intermittent and works partially. 

If its code bug, all pages must 100% fail, cant be, works in dev; fails in prod. But could see you are missing some best practices 

1. PageModel is missing resourceType. Though optional annotation, if you have conditions to read resource, example, request.getResource(), its potential to fail conditionally
2. Happily add `implements Page` and adapters={Page.class, PageModel.class}. You can reuse from ootb interface, and maybe you dont need currentPage, since you are adapting already
3. SimpleNavModel component, dont see issues. But reduce adaptable={Resource.class}. Only if you think you need something from SlingServletRequest, extend its scope, else keep its scope simple to Resource. 
4. The @ChildResource is missing name. Its ok assuming your node name is same `simpleNavItems`. Incase some of your old pages had child nodes in different names and you refactored recently, it ll fail on those legacy pages. 

Once again, if above are really bugs, they must break all your pages consistently. Only possibility I could think is, you had recent refactor that works on new pages, but breaks on old pages. Try to package your production content into dev/local and try reproducing. Need to break first in local and then try fix to validate. 

[gkalyan]

Hi @Amsalek4 

As this issues seems to happening only in PROD/Stage but not on DEV/local and is intermittent.

The issue should with the AEM environment or the way the models are being instantiated,

rather than a problem with the model classes themselves, since you haven't made any recent changes to the code.

As this is intermittent, it can be caused by thread contention or memory issues, which can lead to race conditions. The other issue might be the differences in the configuration, deployment between stage and dev like some dependencies missing in the prod/stage which in local they are present.

Firstly, I would check the configurations first on both the instances to rule that out.

Second, check all the dependencies for this bundles are properly installed and running in stage/prod as in some cases they might installed but not running.

Hope this gives you some direction.

[Jörg_Hoh]

In the stacktrace there is this line:

Caused by: java.lang.IllegalArgumentException: com.allb2bsites.core.models.PageHeadModel represents an interface or an abstract class which cannot be instantiated

That means, that at some point the PageHeadModel (which is an interface! You posted the PageHeadModelImpl class) is tried to be instantiated, and that this is causing the problem.

Can you paste the relevant parts of /apps/allbbsites/components/structure/page/page.html?

[Amsalek4]

Hi @Jörg_Hoh  

Please find the page.html where we have included other html too.

<!DOCTYPE HTML>
<html data-sly-use.page="com.adobe.cq.wcm.core.components.models.Page" lang="${page.language.toLowerCase}"
  data-sly-use.pwa="com.adobe.cq.wcm.core.components.models.PWA" data-sly-use.head="head.html"
  data-sly-use.redirect="redirect.html" data-sly-use.hrefTemplate="href-langs.html"
  data-sly-use.model="com.allb2bsites.core.models.PageHeadModel">

<head data-sly-call="${head.head @ page = page, pwa = pwa, model=model}"></head>

<body class="${page.cssClassNames}" id="${page.id}" data-cmp-data-layer-enabled="${page.data ? true : false}"
  data-nopush="1" data-category="${properties.dataCategory}" data-page="${properties.dataPage}"
  data-index="${properties.dataIndex}" 
  data-acquisition-api-url="${model.acquisitionAPIURL}"
  data-pos-handler="
      {
           &quot;apiUrl&quot;: &quot;${model.currencyCookieAPIURL}&quot;,
           &quot;apiUrlManual&quot;: &quot;${model.currencyCookieManualAPIURl}&quot;,
           &quot;key&quot;: &quot;${model.key}&quot;,
           &quot;siteCode&quot;: &quot;${model.siteCode}&quot;,
           &quot;isoCountryCode&quot;: &quot;${model.ISOCountryCode}&quot;,
           &quot;languageCodeFromPage&quot;: &quot;${model.language}&quot;,
           &quot;pointOfSaleCodeFromPage&quot;: &quot;${model.POSFromPage}&quot;,
           &quot;apiUrlPosCurrencies&quot;: &quot;${model.PosCurrenciesURI}&quot;,
           &quot;apiUrlCurrencyManual&quot;: &quot;${model.CurrencyManualURI}&quot;,
           &quot;apiUrlPosCountries&quot;: &quot;${model.CountriesURI}&quot;

      }
      ">

  <sly data-sly-test="${properties.androidAppBanner}">
    <meta name="google-play-app" content="${properties.androidAppBannerID}">
  </sly>
  <sly data-sly-test="${properties.iosAppBanner}">
    <meta name="apple-itunes-app" content="app-id=${properties.iosAppBannerID}">
  </sly>
  <script data-sly-test.dataLayerEnabled="${page.data}">
    window.adobeDataLayer = window.adobeDataLayer || [];
    adobeDataLayer.push({
      page: JSON.parse("${page.data.json @ context='scriptString'}"),
      event: 'cmp:show',
      eventInfo: {
        path: 'page.${page.id @ context="scriptString"}'
      }
    });
  </script>
  <sly data-sly-test.isRedirectPage="${page.redirectTarget && (wcmmode.edit || wcmmode.preview)}"
    data-sly-call="${redirect.redirect @ redirectTarget = page.redirectTarget}"></sly>


  <sly data-sly-test="${!isRedirectPage}">
    <sly data-sly-include="body.skiptomaincontent.html"></sly>
    <sly data-sly-test="${!wcmmode.edit}" data-sly-include="one-trust.html"></sly>
    <sly data-sly-include="body.html"></sly>
    <sly data-sly-include="pos-handler.html" />
  </sly>
</body>

</html>

[Jörg_Hoh]

data-sly-use.model="com.allb2bsites.core.models.PageHeadModel"

This code will try to instantiate the PageHeadModel interface, which does not work. 

 

data-sly-use.page="com.adobe.cq.wcm.core.components.models.Page" lang="${page.language.toLowerCase}"
data-sly-use.pwa="com.adobe.cq.wcm.core.components.models.PWA" data-sly-use.head="head.html"
data-sly-use.redirect="redirect.html" data-sly-use.hrefTemplate="href-langs.html"

models.Page and models.PWA are interfaces, but all methods have a default implementation, so I assume that the instantiation works for them (I am not a HTL expert). 

[Amsalek4]

After we discussed with the Engineering team , we found the solution.

we had other bundles included in our repo as submodules. One of the model Impl class from the other bundle has been exported in the their bundle manifest header and as well as our manifest header. Due to this, it had conflict intermittently and issue was occurred.  we removed it form our manifest header

[SuprithaN1]

We are also facing the similar issue. Could you please elaborate the root cause?

[Amsalek4]

Have your issue resolved? @SuprithaN1 

If you are using two core bundles , check if you are exporting the model classes twice. that was the cause for us.