Jahia 8

NullPointerException after migrating a module to Jahia 8

Question

After migrating a module to Jahia 8. A NullPointerException is being thrown when accessing some functions. An example stacktrace is as below:

2020-06-15 09:33:50,646: ERROR [RenderChain] - Error while rendering the resource: Resource{node=/modules/testModule/2.0/templates/server-settings-base/configurations/test-configuration/pagecontent/test-configuration, primaryNodeTypeName=‘tmix:testConfiguration', templateType='html', template='default', configuration='module'}

java.lang.NullPointerException
at org.jahia.services.render.webflow.WebflowDispatcherScript.execute(WebflowDispatcherScript.java:182)
at org.jahia.services.render.filter.TemplateScriptFilter.prepare(TemplateScriptFilter.java:139)
at org.jahia.services.render.filter.RenderChain.doFilter(RenderChain.java:167)
at org.jahia.services.render.RenderService.render(RenderService.java:255)
at org.jahia.taglibs.template.include.ModuleTag.render(ModuleTag.java:592)
at org.jahia.taglibs.template.include.ModuleTag.doEndTag(ModuleTag.java:287)
at org.apache.jsp.modules.default_.jmix_005flist.html.list_jsp._jspx_meth_template_005fmodule_005f0(list_jsp.java:597).
...

Cause

The issue was caused by having a dependency on Spring frameworks (e.g. Webflow) which needs to be explicitly declared in the modules POM.xml files. For more information kindly consult Jahia migration guide below:

Jahia 8 Developers Migration guide

Solution

The solution to this is to make sure that Spring dependencies are correctly configured in POM.xml as mentioned in the migration guide. Below is a an example configuration:

...  
<modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.jahia.modules</groupId>
    <artifactId>jahia-modules</artifactId>
    <version>8.0.0.0</version>
  </parent>
  <groupId>org.testModule.modules</groupId>
  <artifactId>testModule</artifactId>
  <version>2.0</version>
  <packaging>bundle</packaging>
  <name>testModule</name>
  <description>This is test module to be compatible with Jahia 8</description>
  <properties>
    <jahia-depends>default,bootstrap3-core,serverSettings</jahia-depends>
    <require-capability>osgi.extender;filter:="(osgi.extender=org.jahia.bundles.blueprint.extender.config)"</require-capability>
  </properties>
  <dependencies>
    ...
  </dependencies>
...