Help to understand Istio mTLS

Hello everyone!

I`m confuse with Istio mTLS documentation. In my case, I have some java applications and now I need to send my client certificate to the server (outside my cluster / mesh) and trust in server certificate. In my java code I know how to do this, but, is it possible to do this without doing changes in java code? I mean, using Istio mTLS?

The following two guides may be helpful to understand Istio mTLS: