Does Java MessageFormat have a platform lineseparator like String.format does?

This is a long shot, but I'm hoping to replace the newline literals in MessageFormat code like

LOG.log(INFO, "message={0}\nAnd extra blank line\n", new String[]{message});

with a platform-independent pattern. The String.format() pattern %n does not work for Logger or MessageFormat. I'd like to avoid passing System.lineseperator as an argument like this:

LOG.log(INFO, "message={0}{1}And a blank line{1}",new String[]{message, System.lineSeparator()});

I don't see any mention of newline or lineseparator in the docs for MessageFormat, but perhaps it is mentioned somewhere else. https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/text/MessageFormat.html

Solution

Does Java MessageFormat have a platform lineseparator like String.format does?

According to my reading of the code, the answer is No.

And there aren't any extant RFEs or Bug reports about this that I can see in the Java or OpenJDK Bug trackers¹.

However, as Joop notes, since you are actually asking this in the context of logging, there are a few other ways to solve this (though not all will be practical):

Ignore the problem. These messages are going into log files. Maybe it doesn't really matter that the line separators in messages in the log files don't always match the platform.
Create a custom subclass of MessageFormat that recognizes a syntax that means "platform specific line separator".
Handle the line separators by translating them in a custom log message appender or formatter; e.g.
- Translate all line separators of the "wrong kind".
- Recognize and translate a magic character sequence ...
Change to a different logging framework that uses java.util.Formatter for message construction. AFAIK, most modern frameworks do.
Submit an RFE.

^{1 - You could read that as "evidence" of how little use there is of MessageFormat in real world / modern applications, or how few people use it in contexts where line separators matter.}

@Bohemian commented:

Why do you want to avoid "passing System.lineseparator as an argument"?

I would have thought that was self-evident. It is clunky.