StringOutOfBoundException Occurs.

package strings;

public class File {
	String rootAdd;
	int locateSlash,locateDot;
	public File(String address){
		setRoot(address);
	}
	public void setRoot(String address){
		rootAdd = address;
	}
	public String getRoot(){
		locateSlash = rootAdd.lastIndexOf("/");
		return (rootAdd.substring(0, locateSlash));
	}
	public String getExt(){
		locateDot = rootAdd.lastIndexOf(".");
		return (rootAdd.substring(locateDot + 1));
	}
	public String getFileName(){
		return (rootAdd.substring((locateSlash + 1), (locateDot)));
	}
}
import java.util.Scanner;
public class FileRun {
	static Scanner scan = new Scanner(System.in);
	public static void main(String[] args){
		File file1 = new File(scan.nextLine());
		System.out.println("Root Address :- " + file1.getRoot());
		try {
			System.out.println("File Name :- " + file1.getFileName());
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("Extention Type :- " + file1.getExt());
		System.out.println(file1.locateSlash);
		System.out.println(file1.locateDot );
		scan.close();
	}
}

I added the exception just to continue the programe running cause i have a problem in the method getName();

I entered this argument, /home/user/index.html

and my stacktrace is - java.lang.StringIndexOutOfBoundsException: String index out of range: -11
at java.lang.String.substring(Unknown Source)
at strings.File.getFileName(File.java:22)
at strings.FileRun.main(FileRun.java:9)