I am running Alfresco Community-5.2.0. I use mmt to install my extension. It reports correctly, but it does not install the jar file. I installed the same extension in another Alfresco installation of the same configuration and that works well.
Here is the commands I used:
[/opt/alfresco-community]$ sudo java -version java version "1.8.0_201" Java(TM) SE Runtime Environment (build 1.8.0_201-b09) Java HotSpot(TM) 64-Bit Server VM (build 25.201-b09, mixed mode)
Installing AMP '*****/alf-exts/montage-qcdoc-share-jar-2.3.amp' into WAR './tomcat/webapps/share.war' Backing up file... The back up is at '/opt/alfresco-community/./tomcat/webapps/share.war-1550201260616.bak' INFO: Checking the war version using the manifest. Adding files relating to version '2.3' of module 'montage-qcdoc-share-jar' - File '/WEB-INF/lib/montage-qcdoc-share-jar-2.3.jar' added to war from amp
That may be "working" by sheer luck of using the default (in my eyes not recommended) configuration of Tomcat of "redeploy=true" - that is very dangerous. Doing this at runtime will dynamically trigger undeploy/redeploy cycles in Tomcat, which may fail due to Alfresco not really cleaning up after itself during an undeploy, which can lead to residual stuff being kept in memory.