Upgrade Tool Uses Wrong Version of Tomcat

Issue

When upgrading to Liferay DXP 7.0 or DXP 7.1 and using the SP1 + Tomcat bundle, the wrong version of Tomcat is suggested by the Upgrade Tool
For 7.1 the bundle includes Tomcat 9.0.6, but the Upgrade Tool is configured to recommend version 9.0.10
For 7.0 the bundle includes Tomcat 8.0.53. Also a "/tools/" is added at the end of the path.

If the user uses the suggested version and path, the upgrade will fail with this error:

Exception in thread "main" java.lang.ClassNotFoundException: com.liferay.portal.tools.DBUpgrader 

at java.net.URLClassLoader.findClass(URLClassLoader.java:381) 

at java.lang.ClassLoader.loadClass(ClassLoader.java:424) 

at java.lang.ClassLoader.loadClass(ClassLoader.java:357) 

at com.liferay.portal.tools.db.upgrade.client.DBUpgraderLauncher.main(DBUpgraderLauncher.java:43)

Environment

Upgrade tool 2.0.1
Liferay DXP 7.0 on a Tomcat Bundle
Liferay DXP 7.1 SP1 + Tomcat Bundle
2023.Q3.1 bundle with the upgrade tool has a similar behavior

Resolution

There are three possible solutions:

When prompted to select the Application Server directory by the Upgrade tool, specify tomcat-9.0.6 or tomcat-8.0.53, instead of using the suggested tomcat 9.0.10.
Also check the paths automatically created and remove the "/tool/" part both on the app-server.properties and the portal-upgrade-ext.properties
For 7.1 the issue will be resolved with the SP2 + Tomcat bundle. Use the Liferay DXP 7.1 GA1 + Tomcat bundle to upgrade and install the latest fix pack.