I have to do one project for my thesis involving Artificial intelligence, collaborative filtering and machine learning methods.

I only know PHP/mysq/JS, and there is not much AI stuff examples in PHP.

There are some books on AI on internet but they use Java , Python.

Now I have to apply AI techniques on web application.

Which language should i choose java or python.

I searhed on internet that I can call java classes inside my php so that can help as as I am very good at php

I have also seen that python can also be used with php as well

So which way should I go and roughly how much it will take me to learn java

I have done java basics but that was 6 years ago

Of the languages you've mentioned, you will probably find the most readily useful tools available in Java, especially for machine learning resources. A good example of this is WEKA, which is a popular data mining tool written in Java.

Machine learning algorithms are generally something you don't want to have to code from scratch if you don't have to. Although you would certainly learn a lot from doing so, they can take a significant amount of time to debug since it can often be hard to tell the difference between working and non-working behavior, e.g., they can sometimes fail to learn either with or without bugs, and they can also learn patterns with or without bugs.

I'd look for tools first, then decide on the language with the tool options in mind.