ICJ is not international rules, it's not even part of UN, it's rules are non binding unless both parties agree to submit to the court. Showing middle finger to ICJ is the right thing to do because ICJ has been pretending to be international law for too long, it is time to bust that disguise.
Chinese patrol is to protect free navigation of Chinese merchant ships, it's clear that India sees itself not to be binded by international rules and will block Chinese shipping line.
Setting up a permanent naval base in Vietnam is not against international rules as long as Vietnam agrees India to do so. But I am not so sure it's going to happen, if you people know something about Vietnamnese, you would understand that they are a group of proud people and won't tolerate military presence of India in their territory.
And some little advice to indian.members, no need to muster your morale in a debate by bringing in third parties like US, Japan, Australia, as if they are indian allies. not necessarily true. these countries are in fact happy to see China taking good care of India as long as India doesn't collapse. And China will manoeuvre its policy carefully without giving the third parties enough incentives to step in while keep on diminishing India's influence in South Asia.