I can launch Confluence with Plugin SDK when I don’t specify a version. The Confluence version is shown to be version 7.
I wanted to experiment with custom emoji, which seems to be in version 8 only. So I cleared cache and chagned the command to add --version parameter:
Executing: "C:\Applications\Atlassian\atlassian-plugin-sdk-8.2.7\apache-maven-3.5.4\bin\mvn.cmd" com.atlassian.maven.plugins:amps-dispatcher-maven-plugin:8.1.2:run -gs C:\Applications\Atlassian\atlassian-plugin-sdk-8.2.7\apache-maven-3.5.4/conf/settings.xml -Dhttp.port=2990 -Dajp.port=8009 -Dproduct=confluence -Djvmargs=-Datlassian.mail.senddisabled=false -Djvmargs=-Xmx6G -Dproduct.version=8.5.0-rc2
Version 8 gets downloaded and launched:
[INFO] [talledLocalContainer] Tomcat 9.x started on port  [INFO] confluence started successfully in 65s at http://localhost:2990/confluence [INFO] Type Ctrl-C to shutdown gracefully
But when I hit the URL, it shows me a blank page.
The log file has nothing in it:
Aug 31, 2023 9:22:20 AM org.apache.jasper.servlet.TldScanner scanJars INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. Aug 31, 2023 9:22:20 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deployment of web application directory [C:\KC\git\PCCW_Confluence\ConfluencePlugin\target\container\tomcat9x\cargo-confluence-home\webapps\manager] has finished in [1,627] ms Aug 31, 2023 9:22:20 AM org.apache.coyote.AbstractProtocol start INFO: Starting ProtocolHandler ["http-nio-2990"] Aug 31, 2023 9:22:20 AM org.apache.catalina.startup.Catalina start INFO: Server startup in  milliseconds
Why does it not work?