New to Java

Hello all, I have got a text file from which I want to remove URL tags, i.e.all the text between the characters "<" and ">" and the "<" and ">" tags themselves. The code below gives me the error 'char cannot be dereferenced'. What is causing this error, and does anyone know what is the best way to remove this type of text?

/** This program reads in a text file and removes the URL tags from it
*
*
*@author Myriam
*
*/

import java.io.*;
import cs1ll4.*;
import java.util.*;

public class Best
{
public static void main (String [] args)
{
try
{
BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(Input.readString("Input Filename:")), "8859_1"));

//open output stream
Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(Input.readString("outfilename:")), "8859_1"));

String line = null ;
while( (line = in.readLine() ) != null)
{
int length = (int)line.length();
char [] characterArray = new char[length];
for (int i = 0; i < length; i++)
//if array(0) is "<", do nothing. else print the line.
{
if((characterArray[0].charAt(0)).equals("<"))
{
}
else
{
out.write(line);
}
}

line = in.readLine();
}

out.flush();
out.close();

//close input and output streams
in.close();
}
catch(IOException e)
{
System.out.println("IOException caught");
System.out.println(e.getMessage());
}
}
}