Trying to write data to a text file using java.io.File

Question

I am trying to create a text file and write data to it by using java.io.File and . I am using JDeveloper 10.1.3.2.0. When I try run the program I get a java.lang.NullPointerException error. Here is the snippet of code that I believe is calling the class that's causing the problem:
String fpath = "/test.html";
FileOutputStream out = new FileOutputStream(fpath);
PrintStream pout = new PrintStream(out);
Do I need to add additional locations for source files or am I doing something wrong? Any suggestions would be appreciated.
Thank you.

Answer 1

Hi dhartle,
May be that can help:
* Class assuming handling logs and connections to the Oracle database
* @author Fabre tristan
* @version 1.0 03/12/07
public class Log {
    private String fileName;
     * Constructor for the log
    public Log(String name) {
        fileName = name;
     * Write a new line into a log from the line passed as parameter and the system date
     * @param   line    The line to write into the log
    public void lineWriter(String line) {
        try {
            FileWriter f = new FileWriter(fileName, true);
            BufferedWriter bf = new BufferedWriter(f);
            Calendar c = Calendar.getInstance();
            Date now = c.getTime();
            String dateLog =
                DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM,
                                               Locale.FRANCE).format(now);
            bf.write("[" + dateLog + "] :" + line);
            bf.newLine();
            bf.close();
        } catch (IOException e) {
            System.out.println(e.getMessage());
     * Write a new line into a log from the line passed as parameter,
     * an header and the system date
     * @param   header  The header to write into the log
     * @param   info    The line to write into the log
    public void lineWriter(String header, String info) {
        lineWriter(header + " > " + info);
     * Write a new long number as line into a log from the line 
     * passed as parameter, an header and the system date
     * @param   header  The header to write into the log
     * @param   info    The line to write into the log
    public void lineWriter(String header, Long info) {
        lineWriter(header + " > " + info);
     * Enable to create folders needed to correspond with the path proposed
     * @param   location    The path into which writing the log
     * @param   name        The name for the new log
     * @return  Log         Return a new log corresponding to the proposed location
    public static Log myLogCreation(String location, String name) {
        boolean exists = (new File(location)).exists();
        if (!exists) {
            (new File(location)).mkdirs();
        Log myLog = new Log(location + name);
        return myLog;
     * Enable to create the connection to the DB
     * @return  Connection  Return a new connection to the Oracle database
    public static Connection oracleConnectionCreation() throws Exception {
        // Register the Oracle JDBC driver
        DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
        //connecting to the DB
        Connection conn =
            DriverManager.getConnection("jdbc:oracle:thin:@myComputerIP:1521:myDB","user", "password");
        return conn;
     * This main is used for testing purposes
    public static void main(String[] args) {
        Log myLog =
            Log.myLogCreation("c:/Migration Logs/", "Test_LinksToMethod.log");
        String directory = "E:\\Blob\\Enalapril_LC-MS%MS_MS%MS_Solid Phase Extraction_Plasma_Enalaprilat_ERROR_BLOB_test";
        myLog.lineWriter(directory);
        System.out.println(directory);
[pre]
This class contained some other functions i've deleted, but i think it still works.
That enables to create a log (.txt file) that you can fill line by line.
Each line start by the current system date. This class was used in swing application, but could work in a web app.
Regards,
Tif