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https://issues.apache.org/jira/browse/LOG4J2-1570?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16711985#comment-16711985
]
Stefan Küttner edited comment on LOG4J2-1570 at 1/13/19 8:15 PM:
-----------------------------------------------------------------
If one starts using functional syntax this issue becomes more serious as more
and more log entries are not attributable to the logging class/line number,
making logs less useful for diagnostics.
Another Example - with only one method - that will produce a weird outcome
telling you the log entry's source was {{Optional.ifPresent}}!:
{code:java}
package com.exxeta.log4j.test;
import java.util.Optional;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.appender.ConsoleAppender;
import org.apache.logging.log4j.core.config.Configurator;
import
org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
import
org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;
public class Log4jThreadAnalyzerErrorDemo
{
private static final Logger LOG;
static
{
configureRootLogger();
LOG = LogManager.getRootLogger();
}
public static void main(String[] args)
{
// This produces "INFO main - (Optional.java:159) - Optional.ifPresent:
Hello World!"
Optional.of("Hello World!").ifPresent(LOG::info);
}
private static void configureRootLogger()
{
ConfigurationBuilder<BuiltConfiguration> builder =
ConfigurationBuilderFactory
.newConfigurationBuilder();
AppenderComponentBuilder console = builder.newAppender("Stdout",
"CONSOLE").addAttribute("target",
ConsoleAppender.Target.SYSTEM_OUT);
console.add(builder.newLayout("PatternLayout").addAttribute("pattern",
"%n%d{dd.MM.yyyy HH:mm:ss} %-5p %t - (%F:%L) - %C{1}.%M:
%m%n"));
builder.add(console);
builder.add(builder.newRootLogger(Level.INFO).add(builder.newAppenderRef("Stdout")));
Configurator.initialize(builder.build());
}
}
{code}
was (Author: stefan.kuettner):
If one starts using functional syntax this issue becomes more serious as more
and more log entries are not attributable to the logging class/line number,
making logs less useful for diagnostics.
> Logging with a lambda expression with a method call that also logs causes
> logs within method call to reference line num and method name as parent method
> --------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: LOG4J2-1570
> URL: https://issues.apache.org/jira/browse/LOG4J2-1570
> Project: Log4j 2
> Issue Type: Bug
> Components: API
> Affects Versions: 2.6.2
> Reporter: Joel Berta
> Priority: Minor
> Labels: easyfix, newbie
>
> While logging a message using lambda expressions. If i call a method within
> the log message (i.e logger.info(() -> "foo" +bar()) which also logs
> messages, those logs within the called method will reference the line number
> and method name of the method which invoked it.
> Running the following code demonstrates this issue:
> {code:title=TestingLogging.java|borderStyle=solid}
> private static final Logger LOGGER =
> LogManager.getLogger(TestingLogging.class);
> public static String foo(){
> LOGGER.info("bar");
> return "foo";
> }
> public static void main(String[] args){
> System.out.println("correct method reference: ");
> LOGGER.info(foo());
> System.out.println("\nincorrect method reference: ");
> // causes logging in foo to reference
> // this line number and method (main)
> LOGGER.info(() -> foo());
> }
> {code}
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