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

apache-commons-loggingjavalog4jlogging

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:

log.info("hey");

 [INFO] [Foo:413] hey

But if have a helper method in between, the actual caller will be the helper method, and that is not too informative.

log_info("hey");

[INFO] [LoggingSupport:123] hey

Is there a way to tell the logging system to remove one frame from the callstack when figuring out the source location to print?

I suppose that this is implementation specific; what I need is Log4J via Commons Logging, but I am interested to hear about other options.

Best Solution

Alternative answer.

It is possible to ask log4j to exclude the helper class by using the method

Category.log(String callerFQCN, Priority level, Object message, Throwable t)

and specifying the helper class as 'callerFQCN'.

For example here is a class using a helper:

public class TheClass {
    public static void main(String...strings) {
        LoggingHelper.log("Message using full log method in logging helper.");
        LoggingHelper.logNotWorking("Message using class info method");
}}

and the code of the helper:

public class LoggingHelper {
private static Logger LOG = Logger.getLogger(LoggingHelper.class);

public static void log(String message) {
    LOG.log(LoggingHelper.class.getCanonicalName(), Level.INFO, message, null);
}

public static void logNotWorking(String message) {
    LOG.info(message);
} }

The first method will output your expected result.

Line(TheClass.main(TheClass.java:4)) Message using full log method in logging helper.
Line(LoggingHelper.logNotWorking(LoggingHelper.java:12)) Message using class info method

When using this method, Log4j will work as usual, avoiding calculating the stack trace if it is not required.