I had the same problem, so I have done a little workaround to achieve a lazy initialized log file, I have used an instance of my own LazyFileOutputStream(http://code.google.com/p/log4j-additions/source/browse/src/org/pollerosoftware/file/LazyFileOutputStream.java) already implemented for log4j in my log4j-additions package(http://code.google.com/p/log4j-additions/) .


Basically I have subclassed the RollingFileAppender logback class in this way :


public class LazyRollingFileAppender<E> extends RollingFileAppender<E> {

/**
* Sets and <i>opens</i> the file where the log output will go. The specified
* file must be writable.
*
* @param file_name
* The path to the log file.
*
* @author Alessio Pollero
*/
@Override
public void openFile(String file_name) throws IOException {
synchronized (lock) {
File file = new File(file_name);

LazyFileOutputStream lazyFos = new LazyFileOutputStream(file, append);
setOutputStream(lazyFos);
}
}

}


I hope this will helps someone ...