How do I read the data of different files into an array?

I have a folder that contains only integer files. User input writes the files so the number of files in the folder always changes.

Here is my code.

       // Returns an array of pathnames of all files in a folder. 
       File[] fileArray = folder.listFiles();

       // For each file in the file array
       for ( File file : fileArray){

       int[] anArray;


       // Reads each file.
       FileReader fr = new FileReader(file);
       anArray[] = fr.read();

I want the FileReader to read the data into anArray. I cannot code the files individually like this,

anArray[0] = fr.read();
anArray[1] = fr.read();

because the number of files always changes. How do I do this?