Fix formatting with single quote arguments for String.format with JUL

[rthaenert]

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• You use the code formatters provided here and have them applied to your changes. Don’t submit any formatting related changes.
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Hey Mark,

we are using logstash-gelf for Applications on JBoss EAP 7.

We noticed that some of the JBoss startup messages are not displayed properly when sending via logstash-gelf.
Example after formatting:
WFLYEJB0473: JNDI bindings for session bean named %s in deployment unit %s are as follows:%s
Message Format Template:
JNDI bindings for session bean named '%s' in deployment unit '%s' are as follows:%s

This message comes from Wildfly (see the following line in Wildfly: https://github.com/wildfly/wildfly/blob/cd1a5e2393052f3a91e77e581dfeee839d6f819d/ejb3/src/main/java/org/jboss/as/ejb3/logging/EjbLogger.java#L3059 ).

The log message has single quotes which get removed by the MessageFormat call. Afterwards a subsequent String.format will not be applied (because the String was changed and is now missing the single quotes).

One easy fix for that is to check whether there is a MessageFormat identifier ("{") inside the message and skip MessageFormat if that's not the case.
Although this won't solve all cases it should be good enough to fix the Startup Messages and not break something else.

[mp911de]

Would it make sense to switch the order of calls (String.format(…), then MessageFormat.format(…))?

[rthaenert]

This idea came up as well.

However, the documentation of java.util.Logger points to MessageFormat (Typically, formatters use java.text.MessageFormat style formatting) and slf4j uses MessageFormat as well in their documentation.

When putting String.format in front of the MessageFormat the following would not work as there is a quote sign somewhere in the message:
logger.error("%sdfsdfk#! {0}", "someParam");
These are rare cases, however I wouldn't feel confident switching the order as this might break someone's log message formatting.

[mp911de]

In any case, having two formatting approaches within the same logger is kind of weird. We can merge this PR. If we encounter further issues, we can add a config property to control formatting order and enablement (formatter=message,format or something like that).

[rthaenert]

Thanks, we'll look out for further issues regarding the formatting.

[mp911de]

Thank you for your contribution. That's merged and polished now.