log4j.appender.ErrFileAppender=com.logger.ErrorFile
log4j.appender.ErrFileAppender.Threshold=WARN
log4j.appender.ErrFileAppender.File=${logdir}/Error.log
log4j.appender.ErrFileAppender.layout=com.logger.header.ErrHeader
log4j.appender.ErrFileAppender.DatePattern='.' yyyy-MM-dd
log4j.appender.ErrFileAppender.layout.ConversionPattern= %m%n

public class RegisterRollingFileAppender extends DailyRollingFileAppender {

    @Override
    public synchronized void setFile(String fileName) {
        // Your logic goes here
        super.setFile(fileName);
        File f = new File(super.getFile());
        RegisterPatternLayout layout = new RegisterPatternLayout();
        if (f.exists()) {
            if (f.length() == 0) {
                super.setLayout(layout);
            } else {
                PatternLayout p = new PatternLayout();
                p.setConversionPattern("%m%n");
                super.setLayout(p);
            }
        }
    }
}