How to configure log4j to only keep log files for the last seven days?

Question

I have the following logging problem with several Java applications using log4j for logging:

I want log files to be rotated daily, like

Answer 1

I create this Methode and call it by closing the application:

  public void deleteFiles(){

    File f = new File("log");
    File[] fileArray = f.listFiles();
    double timenow = System.currentTimeMillis();

    double olderTenDays = timenow - 864000000;// MS for ten days

    for (int i = 0; i < fileArray.length; i++) {

        if(fileArray[i].lastModified()< olderTenDays )
           fileArray[i].delete();
    }
 }