Error in Logs When Accessing "OAuth 2 Administration" in Control Panel

Issue

• When clicking on the "OAuth 2 Administration" option in the Control Panel, the following error is logged, and the UI displays an unresolved Velocity variable (${processor.processMax()}):
  

  Unable to execute method processMax {exception=com.liferay.portal.kernel.portlet.PortletContainerException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class com.sun.proxy.$Proxy12536, className=com.liferay.portal.layoutconfiguration.util.velocity.TemplateProcessor}
  com.liferay.portal.kernel.portlet.PortletContainerException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class com.sun.proxy.$Proxy12536

 Environment

• Liferay DXP 7.4 +

Resolution

• The issue was traced to an overridden bootdelegation configuration in the portal-ext.properties file.
• This configuration interferes with the OSGi class loading mechanism, resulting in a NoClassDefFoundError and failure to initialize the TemplateProcessor proxy class.

• To fix the issue, remove the following property from your portal-ext.properties file:

  ## For AppD
  module.framework.properties.org.osgi.framework.bootdelegation=\
  __redirected,\
  com.liferay.aspectj,\
  com.liferay.aspectj.*,\
  com.liferay.portal.servlet.delegate,\
  com.liferay.portal.servlet.delegate*,\
  com.sun.ccpp,\
  com.sun.ccpp.*,\
  com.sun.crypto.*,\
  com.sun.image.*,\
  com.sun.jmx.*,\
  com.sun.jna,\
  com.sun.jndi.*,\
  com.sun.mail.*,\
  com.sun.management.*,\
  com.sun.media.*,\
  com.sun.msv.*,\
  com.sun.org.*,\
  com.sun.syndication,\
  com.sun.tools.*,\
  com.sun.xml.*,\
  com.yourkit.*,\
  sun.*,\
  org.apache.poi,\
  org.apache.poi.*,\
  net.sf.jasperreports,\
  net.sf.jasperreports.*,\
  com.lowagie,\
  com.lowagie.*,\
  org.apache.commons.logging,\
  org.apache.commons.logging.*,\
  org.apache.commons.digester,\
  org.apache.commons.digester.*,\
  org.apache.commons.collections4,\
  org.apache.commons.collections4.*,\
  org.apache.commons.collections,\
  org.apache.commons.collections.*,\
  org.apache.commons.codec,\
  org.apache.commons.codec.*,\
  org.apache.commons.beanutils,\
  org.apache.commons.beanutils.*,\
  org.bouncycastle,\
  org.bouncycastle.*,\
  com.singularity.*
• After removing the property, perform a clean server restart to ensure all changes take effect.