You can try to enable tls1.2 in Java 7:
https://www.baeldung.com/java-7-tls-v12But probably you need to do code changes.
In my case that was not an option so I cheated. I placed a reverse proxy between Liferay and the service I needed to call. That way Liferay talks with the proxy and the proxy talks with the service.
Let's say, your forum url is
https://discourse.somewhere.com:
1) On the reverse proxy, add a hosts configuration for discourse.somewhere.com
2) Create a self signed certificate for discourse.somewhere.com
3) ProxyPass all requests to "discourse.somewhere.com" to the real discourse.somewhere.com
Test it with curl
4) On the Liferay server, add
discourse.somewhere.com to /etc/hosts with the IP of the reverse proxy
5) Trust that certificate in Liferay (import it in a truststore and configure it to use that truststore)
Since the proxy is yours, you can use all ciphers you want, even those old, deprecated ciphers Java 7 needs.
