log4j / eclipse / linux

[Jan Groth]

hi there,

i'm using log4j since years but this drives me crazy. but until now i was developing on windows with jetbrain's idea, this is my helloworld in eclipse on linux.

my logging.properties is extremely simple, actually it's from the log4j documentation.

log4j.rootLogger=DEBUG, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

i'm passing the location into the JVM as a classpath argument:

-Dlog4j.configuration=config/logging.properties

i'm dumping the system properties in my code, and i can see that the variable realy made it into the JVM

that's how i get my logger:

public static final Logger LOGGER = Logger.getLogger(TriviaTest.class);

and that's how i log:

LOGGER.info("test log info level");

and that's what elipse's console says:

log4j:WARN No appenders could be found for logger (de.jangroth.MobileMusicSync.TriviaTest).
log4j:WARN Please initialize the log4j system properly.

:-(

i have no clue, being stuck here since days...

any ideas?

many thanks & greetings,
jan

[Carol Enderlin]

Try adding debug param, it's probably not finding your properties file:

-Dlog4j.debug

[Jan Groth]

hello carol,

thanks for your reply, this gave me new ideas. please look at the following code:

public void testTrivia() {
Properties props = new Properties(System.getProperties());
String pathFromProperty = props.getProperty("log4j.configuration");
System.out.println("filepath from property " + pathFromProperty);

String filePath = "config/logging.properties";
File file = new File(filePath);
System.out.println("filepath from file object " + file.getPath());

System.out.println("Equal? " + filePath.equals(pathFromProperty));

System.out.println("My classloader " + this.getClass().getClassLoader());

LOGGER.info("test log info level");
assertTrue(true);
}

and here's the system output (with the debug parameter set)

log4j: Trying to find [config/logging.properties] using context classloader sun.misc.Launcher$AppClassLoader@133056f.
log4j: Trying to find [config/logging.properties] using sun.misc.Launcher$AppClassLoader@133056f class loader.
log4j: Trying to find [config/logging.properties] using ClassLoader.getSystemResource().
log4j: Could not find resource: [config/logging.properties].
filepath from property config/logging.properties
filepath from file objectconfig/logging.properties
Equal? true
My classloader sun.misc.Launcher$AppClassLoader@133056f
log4j:WARN No appenders could be found for logger (de.jangroth.MobileMusicSync.TriviaTest).
log4j:WARN Please initialize the log4j system properly.

okay.

debug says that log4j cannot open the resource. but if i read the configuration property manualy, i can build a file object without problems. i'm using the same path as the property is set to.

i'm in the same classloader.

hmm.

any ideas?

;-)

many thanks,
jan.

[Carol Enderlin]

As indicated by the log4j debug it is looking for config/logging.properties on your classpath and it cannot find it. So, is the config directory on the classpath?

log4j short manual

[Jan Groth]

hm, maybe i'm missing something here, but what does the config directory want in my classpath?

if

String filePath = "config/logging.properties";
File file = new File(filePath);
System.out.println("filepath from file object " + file.getPath());

is able to read the config file, why should I add the directory to the classpath?

my interpretation is: the JVM is able to open the file, either addressed like above or through log4j business code... so this cannot be the cause.

i'm doing all my configuration through eclipse, adding my project home & junit.jar & log4j.jar to my project environment. a class path is not set.

i'd say that's not the root of my problem, or am i wrong in my argumentation?

many greetings,
jan

[Carol Enderlin]

I do not see in your code that your File manipulation is actually finding the file. Did you read from the file or do a file.exists() or perhaps see what you get back with getAbsolutePath() or getCanonicalPath()?

Look at the log4j debug output...the classloaders are looking for config/logging.properties and cannot find it.

[Jan Groth]

two issues:

first (and most important): the problem is solved, this article helped me a lot. it was a classpath problem. i was unaware that eclipse seems to interfere the vm-args and needs its own configuraton variable. i don't know if this is for any good reasons, i found intellij-idea far more intuitive for the user

second: concerning your last answer, carol: well, my testcode actually was able to _read_ the whole file, line by line. but my assumption "if _i_ can the file, log4j can too" was wrong. i debugged into the logger, and found that log4j uses (better: tries) different classloaders and their getRessource() methods to load the file. And those fall back on the set class path, no matter if "/config" is reachable from with a eclipse java-program or not. i find this pretty strange... ;-)

many thanks for your help & greetings from berlin / germany,
jan