Vaadin / OSGi：找不到ScssStylesheet类

Question

I use vaadin and OSGi to create a modular application. After a long fight, I was able to deploy successfully the application. However, I can't load the style. When I try to access to http://localhost:8080/myapp/VAADIN/themes/myTheme/styles.css I got the following exception:

exception

javax.servlet.ServletException: Servlet execution threw an exception

root cause

java.lang.NoClassDefFoundError: com/vaadin/sass/internal/ScssStylesheet
com.vaadin.server.VaadinServlet.serveOnTheFlyCompiledScss(VaadinServlet.java:957)
com.vaadin.server.VaadinServlet.serveStaticResourcesInVAADIN(VaadinServlet.java:790)
com.vaadin.server.VaadinServlet.serveStaticResources(VaadinServlet.java:760)
com.vaadin.server.VaadinServlet.service(VaadinServlet.java:257)
com.vaadin.server.VaadinServlet.service(VaadinServlet.java:201)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.ClassNotFoundException: com.vaadin.sass.internal.ScssStylesheet
org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
java.lang.ClassLoader.loadClass(ClassLoader.java:356)
com.vaadin.server.VaadinServlet.serveOnTheFlyCompiledScss(VaadinServlet.java:957)
com.vaadin.server.VaadinServlet.serveStaticResourcesInVAADIN(VaadinServlet.java:790)
com.vaadin.server.VaadinServlet.serveStaticResources(VaadinServlet.java:760)
com.vaadin.server.VaadinServlet.service(VaadinServlet.java:257)
com.vaadin.server.VaadinServlet.service(VaadinServlet.java:201)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)[/code]

com.vaadin.sass.internal.ScssStylesheet class is offered by vaadin-theme-compiler-7.xxjar but the server doesn't import this package. Then, I "hacked" the vaadin server bundle by adding DynamicImport-Package: * in vaadin server's MANIFEST. The previous exception does not appear but I got the same for org.w3c.css.sac.CSSException .

Note that by deploying the application .war file on tomcat, I had no error and the app looks like I expected (because all libraries are added under WEB-INF/lib and tomcat add them on the class loader). So, the problem is pure OSGi.

Answer 1

based on the Vaadin 7.1.3 bundles, the following changes need to be made:

• import com.vaadin.theme-compiler in com.vaadin.server
• import org.w3c.css.sac in com.vaadin.shared.deps and com.vaadin.theme-compiler
• provide a ScssStylesheetResolver via ScssStylesheet.setStylesheetResolvers which loads from bundle resources, not (only) filesystem / classloader as the default implementation.
• if you import parts of the original themes in your theme, consider creating it as a fragment to com.vaadin.themes, which in turn can then be used as a base for the ScssStylesheetResolver

Answer 2

This sounds like a packaging bug in Vaadin which should be reported to the authors. If the core Vaadin bundle needs to access classes from the package com.vaadin.sass.internal then it should include that in its Import-Package header.

With respect to org.w3c.css.sac , you don't specify which bundle throws an error but it sounds like the same kind of problem. Whichever bundle uses that package should import it via Import-Package.