Thread: Apparent bug?

Basically, the program is supposed to ask for the user's name and print it out in reverse and in all lowercase letters.

However, when I run it, Eclipse makes the debugger open... I get "Source not found."

Debugger shows this:

NameReversal [Java Application]
NameReversal at localhost:52896
Thread [main] (Suspended (exception StringIndexOutOfBoundsException))
String.substring(int, int) line: 1762
NameReversal.main(String[]) line: 13
/System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Home/bin/java

Don't know how there could be an error as line 1762...

Here's the code:

import java.io.*;
import java.util.*;
public class NameReversal 
{
	public static void main(String args[])
	{
		Scanner kbreader = new Scanner(System.in);
		System.out.print("Please enter your name. ");
		String name = kbreader.nextLine();
		int howLong = name.length();
		for(int g=howLong;g>=0;g--)
		{
			String reversed = name.substring(g-1,g);
			System.out.print(reversed.toLowerCase());
		}
	}
}

Reeaaalllly confused here.

The error message saying line 1762 is actually referring to the substring method in the String class. Your error is occurring on line 13.

Your loop goes while g is greater than or equal to 0. Inside the loop you substring from g-1 to g. What happens when g is equal to zero? You try to substring from -1 to 0 which throws a StringIndexOutOfBoundsException.

Unless you really have to reverse the string like that I would use a StringBuilder instead.

final StringBuilder stringBuilder = new StringBuilder("String To Reverse");
final String reversedLowerCasedString = stringBuilder.reverse().toString().toLowerCase();

// Json