I search for the java.properties but it not existing on the server.
The JVM Options field is where you put parameters for that. See https://docs.splunk.com/Documentation/DBX/3.13.0/DeployDBX/ConfigureDBConnectsettings#JVM_Options and https://docs.oracle.com/cd/E22289_01/html/821-1274/configuring-the-default-jvm-and-java-arguments.ht...
I was expecting for the specific file but anyway, this solved our issue. thanks!