Try this,
try
{
String input = "";
br = new BufferedReader(new FileReader(inputFile));
out = new PrintWriter(outputFile);
while ((input = br.readLine()) != null)
{
if (input.contains("you"))
{
input = input.replaceAll("you", "we");
out.println(input);
}
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
if (br != null)
{
br.close();
}
if (out != null)
{
out.close();
}
}
catch (IOException ex)
{
ex.printStackTrace();
}
}