Indesign and syntax highlighting

I have a poster which I have made, it is basically lots of java code and looks like a wall of text.

I want to add syntax highlighting to this so that the code is more readable. I know that I can create styles and then apply them by selecting the text and adding the desired style, however there is so much code in the poster that I want t automate/batch this process.

Is there either a plugin I can use that will add the syntax highlighting or is there a way to add styles globally so that it adds the style to every instance of a certain character?

If anyone can think of a different way to achieve this using a different piece of software then please share :)