Print the Stack Trace of the Exception to log file

In Java, when an Exception occurres , the following code snippent can be used to print it in a log file

import java.io.PrintWriter;
import java.io.StringWriter;
    public static String logStackTrace(Throwable t)
    {
         StringWriter sw = new StringWriter();
         PrintWriter pw = new PrintWriter(sw, true);
         exp.printStackTrace(pw);
         pw.flush();
         sw.flush();
         nLog("exception  "+ sw.toString());
    }

    public void nLog(String msg) {
    try {
        BufferedWriter out = new
            BufferedWriter(new FileWriter("/home/temp/ex.log",true));
        out.write(msg+"\n");
        out.close();
        } catch (IOException e) {
           e.printStackTrace();
        }