Creating A System That Will Ask User To Create A File That Will Store To Text File

I am new to java and I am creating a system that will ask the user to create a file that will store to a text file, Once the user created the file I have a class that will let the user input the subject name that has been created, However, I keep on getting this java.util.nosuchelementexception.Here's my code:

public void display_by_name()
{
String id, name,total;
String key[]=new String[30];
String value[]=new String[30];
int i=0;

[code]....