Write Exceptions to File

Question

The java project i have created is to be tested for 1800 cases and the output of each case has to matched with the golden(desired) output. I have created a perl script for this and running it on cygwin.

There are a few cases which throw exceptions but they are wrongly considered to be correct. I want to add a try catch block in java code so that if any exception is thrown it is caught and stack trace is printed on the file exception.txt.

Pseudo Java code:
main()
{
    try
    {
       ... //complete code of main()
    }
    catch (Exception e)
    {
         FileWriter fstream=new FileWriter("exception.txt");
         BufferedWriter out=new BufferedWriter(fstream);
         out.write(e.toString());
         out.close();
    }
}

But this overwrites the previous file contents and finally file contains the last thrown exception. How can i write catch block so that stackTrace is printed and contents of file are intact and not overwritten each time.

Answer 1

Use this constructor instead:

new FileWriter ("exception.txt", true);

It is described here.

EDIT: As per Jon's comment below:

If you want to print the entire stack trace, use printStackTrace:

fw = new FileWriter ("exception.txt", true);
pw = new PrintWriter (fw);
e.printStackTrace (pw);

Also, use the appropriate close calls after that.