In SocketAppenderBase.connect, the Socket constructor is invoked directly to create a new socket. This makes it difficult for a subclass to have any influence over the creation of sockets (e.g. to use an SSL socket).

If SocketAppenderBase declared at method such as this:

protected SocketFactory getSocketFactory() {
return SocketFactory.getDefault()
}

and used it in the connect() implementation...

...
oos = new ObjectOutputStream(getSocketFactory().createSocket(address, port).getOutputStream());
...

then a subclass could override it with, for example, an appropriately configured SSLSocketFactory...

public class MySSLSocketAppender extends SocketAppender {
...
protected SocketFactory getSocketFactory()

...
}