how to get information from any file extension in java

import java.util.LinkedList;
import java.io.File;
public class getFileExtention{
	public static String[] getExt(File path, String extentionType) {
		String [] g = path.list();
		//We need to convert it into a linkedlist for 
        //adding whatever we want any size
		//You could also do it with a number
		//and iterate over it 
		LinkedList<String> h = new LinkedList<String>();
		for(int c = 0;c < g.length;c++) {
			if(g[c].endsWith(extentionType)) {
				h.add(g[c]);
			}
		}
		String[] j = new String[h.size()];
		//Covert it into a array again 
		//but not if you made it into a linked list type method
		for (int d = 0; d < h.size(); d++) {
			j[d] = h.get(d);
		}
		return j;
	}
}