Needed a code for Creating a Log File in java so that its size is limited

Question

Hi
I need the code for developing a log file using threads so that the log file size is limited
and if the size of the log file is increasing above 1Mb,another log file has to be created automatically and the log have to be printed into that new file.
Thanks in advance

Answer 1

package cms.web.log;
import java.io.*;
import java.util.Calendar;
import cms.web.WebUser;
*     Log is generated by JEditor 1.0.0
*     @Project      : cms
*     @Version      : 1.0.0
*     @Created date : 11:07:40  PM Thursday, 25/07/2002
*     @Author       :
*     @Organization :
*     @Copyright    : (c) 2002
*     An utility class used to write information, especially error messages, to
*     log file so that they can be viewed at later time by administrators.
*     Extra information such as date & time they occures & where they are thrown...
*     are automatically included and append to the end of log file.
*     Log files will increase with the format "name_n" where n is file counter
public class Log implements Serializable
      *     logs marker
     static final String START= "\n\0";
      *     parent directory that contains log files
     private static File parent;
     private PrintStream out;
     private String name;
      *     to count how many log for the current stream
     int counter;
      *     maximum number of logs for each log file
     int max;
     public static void init(File parent)
          if (!parent.exists())
               parent.mkdirs();
          Log.parent= parent;
     public Log(String name, int max)
          this.name= name;
          this.max= max;
          file= getLastFile();
          counter= countLogs(file);
          out= openStream(file);
     public synchronized void appendLog(String log)
          if (log == null || log.length() == 0)
               return;
          count();
          try {
               out.println(START+ counter+ " | "+ getCurrentTime()+ " | "+ log);
               out.flush();
          } catch (Exception e) {}
      *     Append the given log to log file.
     synchronized void appendLog(String msg, WebUser user)
          if (msg == null || msg.length() == 0)
               return;
          count();
          try {
               out.println(START+ counter+ "----------------------------------------------------------");
               out.println(getCurrentTime());
               out.println(user != null? "User:"+ user.getFullName(): "User: public user");
               out.println(msg);
               out.println("\n----------------------------- end -----------------------------\n");
               out.flush();
          } catch (Exception e) {}
      *     Append the given exception to log file
     synchronized void appendLog(Throwable error, WebUser user)
          if (error == null)
               return;
          count();
          synchronized (out)
               try {
                    out.println(START+ counter+ "----------------------------------------------------------");
                    out.println("Exception occured at "+ getCurrentTime());
                    out.println(user != null? "User: "+ user.getFullName(): "User: public user");
                    error.printStackTrace(out);
                    out.println("----------------------------- end -----------------------------\n");
                    out.flush();
               } catch (Exception e) {}
     private String getCurrentTime()
          Calendar c= Calendar.getInstance();
          return
               parse(c.get(Calendar.HOUR_OF_DAY))+ ":"+               // 0 --> 23
               parse(c.get(Calendar.MINUTE))+ ":"+                     // 0 --> 59
               parse(c.get(Calendar.SECOND))+ " "+                     // 0 --> 59
               parse(c.get(Calendar.DAY_OF_MONTH))+ "/"+                 // 1 --> 31
               parse(c.get(Calendar.MONTH)+ 1)+ "/"+                     // 1 --> 12
               c.get(Calendar.YEAR);                                        // yyyy
     private String parse(int n)
          return n< 10? "0"+ n: ""+ n;
     private void count()
          counter++;
          if (counter> max)
               incrementFile();
               counter= 1;
     private void incrementFile()
          File file= null;
          int n= 0;
          while ((file= new File(parent, name+ n+ ".log")).exists())
               n++;
          if (out != null)
               out.close();
          out= openStream(file);
     private PrintStream openStream(File file)
          try {
               if (file.exists())
                    return new PrintStream(new FileOutputStream(file.getPath(), true));
               else
                    return new PrintStream(new FileOutputStream(file.getPath()));
          } catch (IOException e) {
               throw new RuntimeException(e.getMessage());
     private int countLogs(File file)
          int count= 0;
          InputStream in= null;
          try {
               in= new FileInputStream(file);
               int n;
               while ((n= in.read()) != -1)
                    if (n == '\0')
                         count++;
          } catch (IOException e) {
          } finally {
               if (in != null)
                    try {
                         in.close();
                    } catch (IOException e) {}
          return count;
     private File getLastFile()
          File file= new File(parent, name+ "0.log");
          File curr;
          int n= 1;
          while ((curr= new File(parent, name+ n+ ".log")).exists())
               file= curr;
               n++;
          return file;
     protected void finalized()
          if (out != null)
               out.close();