Develop Reference

PropertyConfigurator for Log4j does not exists anymore?

I only get this on the console:
13:08:18.379 [main] ERROR log4.prueba - This is Error
13:08:18.381 [main] FATAL log4.prueba - This is Fatal
I dont get a file or all the other levels.
What I am doing wrong?
My directory looks like this:
projectFolder/src/log4/prueba.java
projectFolder/src/log4j.properties
The code:
package log4;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class prueba {
private static Logger logger = LogManager.getLogger(prueba.class);
public static void main( String[] args )
{
logger.debug("This is Debug");
logger.info("This is Info");
logger.warn("This is Warn");
logger.error("This is Error");
logger.fatal("This is Fatal");
}
}
And the properties file look like this:
# Root logger option
log4j.rootLogger=DEBUG, file, stdout
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=C:\\logging.log
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p
%c{1}:%L - %m%n
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p
%c{1}:%L - %m%n

Log4j 2 also supports configuration in properties files, but be aware:
the file needs to be called log4j2.properties
the configuration syntax is different from the Log4j 1.2 syntax (the configuration in the question uses the old Log4j 1.2 syntax, Log4j 2 will not understand this)
The Log4j 2 user manual has mostly XML examples, so many people find it easier to use the XML configuration syntax. (Again, the config file should be named log4j2.xml, Log4j 2 will ignore log4j.xml.)

define log4j property file
# prueba.java
import org.apache.log4j.Logger;
public class prueba {
private static Logger LOGGER = Logger.getLogger(prueba.class);
public static void main(String[] args) {
LOGGER.debug("This is Debug");
...
}
}
# pom.xml
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>
at src/resources/log4j.properties
# Root logger option
log4j.rootLogger=DEBUG, file, stdout
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=log/log4j-application.log
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
output to stdout and log/log4j-application.log file
2018-05-11 14:29:43 DEBUG prueba:8 - This is Debug
2018-05-11 14:29:43 INFO prueba:9 - This is Info
2018-05-11 14:29:43 WARN prueba:10 - This is Warn
2018-05-11 14:29:43 ERROR prueba:11 - This is Error
2018-05-11 14:29:43 FATAL prueba:12 - This is Fatal

log4j:ERROR setFile(null,false) call failed with no proper message under java.io.FileNotFoundException:

I am not understanding the error in my log4j.xml. Also I do not see much details under the filenotfoundexception to find the proper issue. Can you please check into the below code and point where I am wrong?
#Application Logs
log4j.logger.devpinoyLogger=DEBUG, dest1, stdout
log4j.additivity.devpinoyLogger=false
log4j.additivity.initLogger=false
#file appender
log4j.appender.dest1=org.apache.log4j.RollingFileAppender
log4j.appender.dest1.maxFileSize=5000KB
log4j.appender.dest1.maxBackupIndex=3
log4j.appender.dest1.layout=org.apache.log4j.PatternLayout
log4j.appender.dest1.layout.ConversionPattern=%d{dd/MM/yyyy HH:mm:ss} %-5p %c %m%n
log4j.appender.dest1.File=${catt.log}
#do not append the old file. Create a new log file everytime
log4j.appender.dest1.Append=false
#console appender
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
log4j.logger.initLogger=DEBUG, init
log4j.appender.init=org.apache.log4j.RollingFileAppender
log4j.appender.init.maxFileSize=5000KB
log4j.appender.init.maxBackupIndex=3
log4j.appender.init.layout=org.apache.log4j.PatternLayout
log4j.appender.init.layout.ConversionPattern=%d{dd/MM/yyyy HH:mm:ss} %-5p %c %m%n
log4j.appender.init.File=C:\\CATT\\Application.txt
#log4j.appender.init.File=${init.log}
#do not append the old file. Create a new log file everytime
log4j.appender.init.Append=false
Exception is :
log4j:ERROR setFile(null,false) call failed.
java.io.FileNotFoundException:
at java.io.FileOutputStream.open0(Native Method)
at java.io.FileOutputStream.open(FileOutputStream.java:270)
at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
at java.io.FileOutputStream.<init>(FileOutputStream.java:133)
at org.apache.log4j.FileAppender.setFile(FileAppender.java:289)
at org.apache.log4j.RollingFileAppender.setFile(RollingFileAppender.java:167)
at org.apache.log4j.FileAppender.activateOptions(FileAppender.java:163)
at org.apache.log4j.config.PropertySetter.activate(PropertySetter.java:256)
at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:132)
at org.apache.log4j.config.PropertySetter.setProperties(PropertySetter.java:96)
at org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:654)
at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:612)
at org.apache.log4j.PropertyConfigurator.parseCatsAndRenderers(PropertyConfigurator.java:533)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:417)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:441)
at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:470)
at org.apache.log4j.LogManager.<clinit>(LogManager.java:122)
at org.apache.log4j.Logger.getLogger(Logger.java:104).
For the line:
Logger.getLogger("initLogger");

Why is Log4j2 throwing an error in Windows bash console

Good morning,
using log4j2 in my project (see below the configuration) running it, everything went ok in Eclipse. Then building the jar and executing it in a bash Windows, I get an error thrown regarding the "Console Appender". After investigation, it works in other shells (like git bash), my question here is about if this behavior is documented somewhere ?(because after googling it a lot, I did not find anything relevant).
My log4j2.properties:
name=PropertiesConfig
property.directory = ./logs
appenders = console, file, testFile
appender.console.type = Console
appender.console.target =SYSTEM_OUT
appender.console.name = STDOUT
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = [%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} line %L - %msg%n
appender.file.type = File
appender.file.append = false
appender.file.name = LOGFILE
appender.file.fileName=${directory}/neoswitcher-${date:yyyy-MM-dd-HH-mm-ss}.log
appender.file.layout.type=PatternLayout
appender.file.layout.pattern=[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n
appender.testFile.type = File
appender.testFile.append = false
appender.testFile.name = LOGTestFILE
appender.testFile.fileName=${directory}/test-suite-${date:yyyy-MM-dd-HH-mm-ss}.log
appender.testFile.layout.type=PatternLayout
appender.testFile.layout.pattern=[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n
loggers=file
logger.file.name=org.test.controller.core
logger.file.level = info
logger.file.appenderRefs = file
logger.file.appenderRef.file.ref = LOGFILE
loggers=file
logger.testFile.name=org.simpleperftests.core;
logger.testFile.level = info
logger.testFile.appenderRefs = testFile
logger.testFile.appenderRef.file.ref = LOGTestFILE
rootLogger.level = info
rootLogger.appenderRefs = stdout, file, testFile
rootLogger.appenderRef.stdout.ref = STDOUT
rootLogger.appenderRef.file.ref = LOGFILE
rootLogger.appenderRef.testFile.ref = LOGTestFILE
And here the error occuring in the MS-DOS console:
2017-02-24 10:55:11,994 main ERROR Unable to inject fields into builder class for plugin type class org.apache.logging.log4j.core.appender.ConsoleAppender, element Cons
ole. java.nio.charset.UnsupportedCharsetException: sun.stdout.encoding
at java.nio.charset.Charset.forName(Charset.java:531)
at org.apache.logging.log4j.util.PropertiesUtil.getCharsetProperty(PropertiesUtil.java:146)
at org.apache.logging.log4j.util.PropertiesUtil.getCharsetProperty(PropertiesUtil.java:134)
at org.apache.logging.log4j.core.appender.ConsoleAppender$Target.getCharset(ConsoleAppender.java:85)
at org.apache.logging.log4j.core.appender.ConsoleAppender$Target$1.getDefaultCharset(ConsoleAppender.java:71)
at org.apache.logging.log4j.core.appender.ConsoleAppender$Builder.build(ConsoleAppender.java:218)
at org.apache.logging.log4j.core.appender.ConsoleAppender$Builder.build(ConsoleAppender.java:185)
at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:122)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:952)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:892)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:884)
at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:508)
at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:232)
at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:244)
at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:545)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:551)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:537)
at org.test.controller.core.App.<clinit>(App.java:14)
2017-02-24 10:55:12,001 main ERROR Unable to invoke factory method in class class org.apache.logging.log4j.core.appender.ConsoleAppender for element Console. java.lang.
IllegalStateException: No factory method found for class org.apache.logging.log4j.core.appender.ConsoleAppender
at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.findFactoryMethod(PluginBuilder.java:224)
at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:130)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:952)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:892)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:884)
at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:508)
at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:232)
at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:244)
at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:545)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:551)
at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:537)
at org.test.controller.core.App.<clinit>(App.java:14)
2017-02-24 10:55:12,012 main ERROR Null object returned for Console in Appenders.
2017-02-24 10:55:12,012 main ERROR Unable to locate appender "STDOUT" for logger config "root"
Edit: It actually works fine on Linux with that version

After testing with the snapshot release (version 2.8.1-SNAPSHOT), the bug is fixed.
The snapshot versions for log4j2 are available at this repository: https://repository.apache.org/content/repositories/snapshots/

Using version 2.8.1 instead of 2.8.0 seemed to resolved the issue for me
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.8.1</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.1</version>
</dependency>

I also had same issue in Windows command promt. I tried in Git Bash and it is working fine as usual.
So, install Git Bash and try in Git Bash, it should work fine.

ClearNLP (NLP4J) parser Error Execute

I'm trying to train with ClearParser and I get this error. Before execute the command I put export CLASSPATH=nlp4j-1.1.0.jar:. and doing java edu.emory.mathcs.nlp.bin.Version I get the version info, so it's installed correctly.
Command line: java -Xmx5g -XX:+UseConcMarkSweepGC edu.emory.mathcs.nlp.bin.NLPTrain -mode dep -c config-train-dep.xml -t /home/iago/Escritorio/idiomasClearParser/UD_English/en-ud-train.conllu -d /home/iago/Escritorio/idiomasClearParser/UD_English/en-ud-dev.conllu -m bestModel-dep.xz
I'm using this config file: https://github.com/emorynlp/nlp4j/blob/master/src/main/resources/edu/emory/mathcs/nlp/configuration/config-train-dep.xml
Error: log4j:WARN No appenders could be found for logger (edu.emory.mathcs.nlp.common.util.BinUtils). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. java.io.FileNotFoundException: edu/emory/mathcs/nlp/lexica/en-brown-clusters-simplified-lowercase.xz (No existe el archivo o el directorio) at java.io.FileInputStream.open0(Native Method) at java.io.FileInputStream.open(FileInputStream.java:195) at java.io.FileInputStream.<init>(FileInputStream.java:138) at java.io.FileInputStream.<init>(FileInputStream.java:93) at edu.emory.mathcs.nlp.common.util.IOUtils.createFileInputStream(IOUtils.java:147) at edu.emory.mathcs.nlp.common.util.IOUtils.getInputStream(IOUtils.java:316) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:82) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:72) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:64) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:55) at edu.emory.mathcs.nlp.bin.NLPTrain$1.createGlobalLexica(NLPTrain.java:108) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:193) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:187) at edu.emory.mathcs.nlp.bin.NLPTrain.train(NLPTrain.java:76) at edu.emory.mathcs.nlp.bin.NLPTrain.main(NLPTrain.java:115) java.io.IOException: Stream closed at java.io.BufferedInputStream.getInIfOpen(BufferedInputStream.java:159) at java.io.BufferedInputStream.fill(BufferedInputStream.java:246) at java.io.BufferedInputStream.read1(BufferedInputStream.java:286) at java.io.BufferedInputStream.read(BufferedInputStream.java:345) at java.io.DataInputStream.readFully(DataInputStream.java:195) at java.io.DataInputStream.readFully(DataInputStream.java:169) at org.tukaani.xz.SingleXZInputStream.initialize(Unknown Source) at org.tukaani.xz.SingleXZInputStream.<init>(Unknown Source) at org.tukaani.xz.XZInputStream.<init>(Unknown Source) at org.tukaani.xz.XZInputStream.<init>(Unknown Source) at edu.emory.mathcs.nlp.common.util.IOUtils.createXZBufferedInputStream(IOUtils.java:220) at edu.emory.mathcs.nlp.common.util.IOUtils.createObjectXZBufferedInputStream(IOUtils.java:259) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:82) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:72) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:64) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:55) at edu.emory.mathcs.nlp.bin.NLPTrain$1.createGlobalLexica(NLPTrain.java:108) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:193) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:187) at edu.emory.mathcs.nlp.bin.NLPTrain.train(NLPTrain.java:76) at edu.emory.mathcs.nlp.bin.NLPTrain.main(NLPTrain.java:115) Exception in thread "main" java.lang.NullPointerException at java.io.ObjectInputStream$PeekInputStream.read(ObjectInputStream.java:2338) at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2351) at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2822) at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:804) at java.io.ObjectInputStream.<init>(ObjectInputStream.java:301) at edu.emory.mathcs.nlp.common.util.IOUtils.createObjectXZBufferedInputStream(IOUtils.java:259) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:82) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.getLexiconFieldPair(GlobalLexica.java:72) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:64) at edu.emory.mathcs.nlp.component.template.util.GlobalLexica.<init>(GlobalLexica.java:55) at edu.emory.mathcs.nlp.bin.NLPTrain$1.createGlobalLexica(NLPTrain.java:108) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:193) at edu.emory.mathcs.nlp.component.template.train.OnlineTrainer.train(OnlineTrainer.java:187) at edu.emory.mathcs.nlp.bin.NLPTrain.train(NLPTrain.java:76) at edu.emory.mathcs.nlp.bin.NLPTrain.main(NLPTrain.java:115)
Why I'm getting this error? I unpacked the .jar and there is no "lexica" folder neither "en-brown-clusters-simplified-lowercase.xz". Where I can found it?
Regards

I found the solution, this error happens because you don't have the "log4j.properties" configured so "nlp4j" can't find it. To fix it only create the file on the same folder that the .jar with this simple code (if you want more details adapt it to your needs)
# Root logger option
log4j.rootLogger=INFO, file, stdout
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File= /path/to/file
log4j.appender.file.MaxFileSize=5MB #Set what you need
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
Moreover, to solve the problem of lexica. Go to this url and download the jars lexica url
Then, on the config xml set the correct path to the jars.
And now it should works. Hope it helps someone.

How to add log4j to a web application in java

I am trying to add log4j to my web application to record the exchange between the server and the client so I added the dependency in my pom.xml:
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
and I created the log4j.proporties:
# Root logger option
log4j.rootLogger=INFO, file
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
#Redirect to Tomcat logs folder
#log4j.appender.file.File=${catalina.home}/logs/logging.log
log4j.appender.file.File=C:\\test.log
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%
and the following is my code :
static final Logger logger = Logger.getLogger(hellologger.class);
public static void main(String[] args) {
String log4JPropertyFile = "C:\\Users\\xxxx\\Desktop\\log4j.properties";
Properties p = new Properties();
try {
p.load(new FileInputStream(log4JPropertyFile));
PropertyConfigurator.configure(p);
logger.info("Wow! I'm configured!");
} catch (IOException e) {
}
}
But finally I got this error :
Infos: org.osgi.framework.BundleException: Unresolved constraint in bundle com.mycompany.webclient [329]: Unable to resolve 329.7: missing requirement [329.7] osgi.wiring.package; (&(osgi.wiring.package=org.apache.log4j)(version>=1.2.0)(!(version>=2.0.0)))
at org.apache.felix.framework.Felix.resolveBundleRevision(Felix.java:3974)
at org.apache.felix.framework.Felix.startBundle(Felix.java:2037)
at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:955)
at org.apache.felix.fileinstall.internal.DirectoryWatcher.process(DirectoryWatcher.java:1175)
at org.apache.felix.fileinstall.internal.DirectoryWatcher.process(DirectoryWatcher.java:1153)
at org.apache.felix.fileinstall.internal.DirectoryWatcher.processAllBundles(DirectoryWatcher.java:1146)
at org.apache.felix.fileinstall.internal.DirectoryWatcher.process(DirectoryWatcher.java:456)
at org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:263)
any idea how to fix this problem ?!!!!

You can go through this tutorial on log4j .
The properties file and pom.xml files are explained properly .
logs generated are like this :
2014-07-02 20:52:39 DEBUG HelloExample:19 - This is debug : mkyong
2014-07-02 20:52:39 INFO HelloExample:23 - This is info : mkyong
2014-07-02 20:52:39 WARN HelloExample:26 - This is warn : mkyong
2014-07-02 20:52:39 ERROR HelloExample:27 - This is error : mkyong
2014-07-02 20:52:39 FATAL HelloExample:28 - This is fatal : mkyong