Java logging example

.gitignore

/build/
.classpath
.settings
.project

ClassA.java

package net.eggplant.mtu;

import java.util.logging.Logger;

public class ClassA {

  private static final Logger LOGGER = logging.LogUtils.getLogger();
  
  public void logInfo() {
    LOGGER.info("info Coming from ClassA");
  }

  public void logFine() {
    LOGGER.fine("fine Coming from ClassA");
  }

}

ClassB.java

package net.eggplant;

import java.util.logging.Logger;

public class ClassB {

  private static final Logger LOGGER = logging.LogUtils.getLogger();
  
  public void logInfo() {
    LOGGER.info("info Coming from ClassA");
  }

  public void logFine() {
    LOGGER.fine("fine Coming from ClassA");
  }

}

JavaLogging.java

package logging;

import java.io.IOException;
import java.io.InputStream;
import java.util.logging.LogManager;

public class JavaLogging {

  private static void configureLogging() throws SecurityException, IOException {
    try (final InputStream stream = JavaLogging.class.getResourceAsStream("logging.properties")) {
      LogManager.getLogManager().readConfiguration(stream);
    }

  }

  public static void main(final String[] args) throws SecurityException, IOException {
    configureLogging();

    net.eggplant.mtu.ClassA classA = new net.eggplant.mtu.ClassA();    
    net.eggplant.ClassB classB = new net.eggplant.ClassB();
    
    classA.logInfo();
    classB.logInfo();

    classA.logFine();
    classB.logFine();

  }
}

logging.properties

handlers = java.util.logging.ConsoleHandler


java.util.logging.ConsoleHandler.level     = ALL
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter

java.util.logging.SimpleFormatter.format=%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s [%3$s] %4$s: %5$s%n

# default level for all loggers
.level = INFO

net.eggplant.ClassB.level  = ALL

net.eggplant.level  = ALL

LogUtils.java

package logging;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.logging.LogManager;
import java.util.logging.Logger;

public class LogUtils {

  /**
   * Automatically gets logger for class calling this method. This method also
   * ensures that a {@link BufferedAppender} is added to the default appenders
   * until log4j is configured.
   */
  public static Logger getLogger() {
    final StackTraceElement[] elements = new RuntimeException().getStackTrace();
    boolean useNextElement = false;
    for (final StackTraceElement element : elements) {
      if (!useNextElement) {
        if (element.getClassName().equals(LogUtils.class.getName())
            && element.getMethodName().equals("getLogger")) {
          useNextElement = true;
        }
      } else {
        return Logger.getLogger(element.getClassName());
      }
    }
    // cannot find logger, this is odd, return Root Logger
    Logger.getGlobal().warning("Cannot find logger for calling class with stack trace, returning root logger:"
        + Arrays.asList(elements));
    return Logger.getGlobal();
  }
}

run.sh

rm -r build
mkdir build
javac *.java -d build
cp logging.properties build/logging/logging.properties
java -classpath build logging.JavaLogging