I followed the following guide to update our Confluence: Upgrading Confluence | Confluence Data Center and Server 7.18 | Atlassian Documentation
After the install process was finished I went trough the Re-apply any modificiations. Once I was done with these, I started up confluence and waited a good 5 to 8 minutes. I was never able to see the confluence web page as it just spun and spun. I looked at the log and found these in the log:
20-Jul-2022 16:04:13.409 INFO [Catalina-utility-2] org.apache.catalina.core.ApplicationContext.log 1 Spring WebApplicationInitializers detected on classpath
20-Jul-2022 16:04:13.564 INFO [Catalina-utility-2] org.apache.catalina.core.ApplicationContext.log Initializing Spring DispatcherServlet 'dispatcher'
16:04:13 [Catalina-utility-2] o.a.c.c.C.[.[.[/synchrony-proxy][INFO] log - Initializing Spring DispatcherServlet 'dispatcher'
2022-07-20 16:04:14,133 INFO [Catalina-utility-1] [com.atlassian.confluence.lifecycle] contextInitialized Starting Confluence 7.18.3 [build 8804 based on commit hash 8aa9917e1c4021c0b260708b5b793e53b1c270dc] - synchrony version 4.1.0
2022-07-20 16:04:17,260 WARN [Catalina-utility-1] [confluence.impl.setup.DefaultBootstrapDatabaseAccessor] lambda$getBootstrapData$3 Unable to determine finalized build number from database [message: Unknown column 'FINALIZED' in 'where clause']. If you are upgrading from a Confluence version prior to 7.14, this is expected.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.apache.felix.framework.ext.ClassPathExtenderFactory$DefaultClassLoaderExtender (file:/opt/atlassian/confluence/confluence/WEB-INF/lib/org.apache.felix.framework-5.6.12.jar) to method java.net.URLClassLoader.addURL(java.net.URL)
WARNING: Please consider reporting this to the maintainers of org.apache.felix.framework.ext.ClassPathExtenderFactory$DefaultClassLoaderExtender
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Exception in thread "I/O dispatcher 7" java.lang.OutOfMemoryError: Java heap space
Exception in thread "I/O dispatcher 6" java.lang.OutOfMemoryError: Java heap space
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "C3P0PooledConnectionPoolManager[identityToken->2sadqaaq85xnv8cjyi6r|2e71817b]-AdminTaskTimer"
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "httpclient-io:thread-1"
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "diagnostics-http-thread"
Exception in thread "logback-7" java.lang.OutOfMemoryError: Java heap space
Exception in thread "logback-8" java.lang.OutOfMemoryError: Java heap space
Exception in thread "logback-6" java.lang.OutOfMemoryError: Java heap space
