If one compiles and updates zabbix binaries (including java gateway) from sources (make install), then corresponding ./bin folder will contain many .jar files like zabbix-java-gateway-2.4.3.jar, zabbix-java-gateway-2.4.4.jar etc
Then startup.sh will start java vm with all these .jar files loaded:

CLASSPATH="lib"
for jar in lib/*.jar bin/*.jar; do
        CLASSPATH="$CLASSPATH:$jar"
done

Need to improve the code block to load for example only one (sort + select only last ?) .jar file.

Also, I don't understand why do we use versioning in .jar file name at all ?
It leads to inconveniences.

For example (in my own internal scripts to "install/deploy" development branches etc) to workaround the version suffix presence I had to use something like:

ls -l ./src/zabbix_java/bin/* &> /dev/null && cp ./src/zabbix_java/bin/* $BINARIES/$BRANCH/bin/zabbix-java-gateway.jar

to copy zabbix-java-gateway-2.4.4.jar as zabbix-java-gateway.jar
This is an example that we indeed could review the version inclusion approach and exclude it.