error related to exception handling in java

How to resolve this error? I have tried using throws to throw FileNotFoundException but still same error.

Compile-Time Error : "Default constructor cannot handle exception type Exception thrown by the implicit super constructor. Must define an explicit constructor "

CODE :

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class FileOne {
Scanner sc = new Scanner(System.in);
String file_name = sc.nextLine();
File obj = new File(file_name);
Scanner reader_obj = new Scanner(obj); // <--- error in this line
public static void main(String args[]) {
FileOne f = new FileOne();
f.create();
f.writeFile();
f.readFile();
}
void create() {
try {
System.out.println("Enter a file name");
if (obj.createNewFile()) {
System.out.println("file name is" + obj.getName());
} else {
System.out.println("Already exists");
}
} catch (IOException e) {
System.out.println("error occured while creating");
}
}
//method to write in file
void writeFile() {
try {
FileWriter w = new FileWriter(obj);
w.write("Learning files now");
w.close();
} catch (IOException e) {
System.out.println("Exception occured while writing a file");
}
}
//method to read
/* use the Scanner class to read the contents of the text file created */
void readFile() {
while (reader_obj.hasNextLine()) {
String data = reader_obj.nextLine();
System.out.println(data);
}
reader_obj.close();
}
}

The line Scanner reader_obj=new Scanner(obj);, which is implicitly called by the default constructor, may throw a FileNotFoundException, which is a checked exception and must be handled.

One way of doing so is explicitly defining a no-arg constructor:

public FileOne() throws FileNotFoundException {
}

Although, if you're going to do that, you should consider moving the members' initialization in to it for clarity's sake.

Errors Resolved:

1. I used throws to throw exceptions in main() and reading() method.
2. Used FileReader class to read the data from the given input file

Final Code:

public class FileOne {
Scanner sc=new Scanner(System.in);
String file_name=sc.nextLine();
File obj=new File(file_name);
//method for creating a file
void create(){
try{
if(obj.createNewFile()){
System.out.println("file name is"+obj.getName());
}
else{
System.out.println("Already exists");
}
}
catch(IOException e){
System.out.println("error occured while creating");
}    
}
//method to write in file
void writeFile(){
try{
FileWriter w=new FileWriter(obj);
w.write("Learning files now");
w.close();
}
catch(IOException e){
System.out.println("Exception occured while writing a file");
}
}
void reading() throws FileNotFoundException,IOException{
FileReader reader=new FileReader(file_name);
int i;
while((i=reader.read())!=-1){
System.out.print((char)i);
}
reader.close();
}
public static void main(String args[])throws FileNotFoundException,IOException{
FileOne f=new FileOne();
f.create(); 
f.writeFile();
f.reading();  
}
}

Add the constructor as below :

public FileOne () throws FileNotFoundException {
}

Edit your void main () as below (You need to throw the exception from main as well) :

public static void main(String args[]) throws FileNotFoundException {
FileOne f = new FileOne();
f.create();
f.writeFile();
f.readFile();
}