Java Logging: show the source line number of the caller (not the logging helper method)

Question

The numerous (sigh...) logging frameworks for Java all do a nice job of showing the line number of the source file name for the method that created the log message:

Answer 1

Adding details to KLE answer. (sorry, noob user, don't know better way than creating a separate answer )

Instead of sticking the line number to the message, you can put it in the MDC context. See org.apache.log4j.MDC

For example:

StackTraceElement[] stackTraces = Thread.currentThread().getStackTrace();
StackTraceElement stackTraceElement = ...;
int l = stackTraceElement.getLineNumber();

MDC.put("myLineNumber", l);

That allows users to use mylineNumber in their log4j configuration file

Note: that allows the user to control where and how the line number appears in the message. However, since getting the stacktrace is very costly, you still need to find a way to switch off the feature.