Having trouble with JSON Object on publish instance

Hello every one!

This time I came here for your help, here's the case:

I developed a custom assets gallery using a Java class that take the metadata of the images and pass it to the html, also I build in this class with the metadata of every image a Json Object that later use on a JavaScript file, until here everything work's fine on my author instance!

The thing is, when I publish the page with component everytthing work's fine but my json object. The image metadata is correctly fill with all the info, but the json object is empty.

My question is: Why this object is getting empty? what's the diference between author and publish instance?