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Java Logging API creating empty log files

I tried to go through the Java Logging API tutorial:

www.vogella.com/articles/Logging/article.html

But the generated files are empty (tested in Netbeans, Eclipse, as well as running jar from cmd). Log messages are displayed only in the console.

The following are the files used in the project. What could be causing this behavior?

Project: de.vogella.logger

MyHtmlFormatter.java

package de.vogella.logger; import java.text.SimpleDateFormat; import java.util.Date; import java.util.logging.Formatter; import java.util.logging.Handler; import java.util.logging.Level; import java.util.logging.LogRecord; //This custom formatter formats parts of a log record to a single line class MyHtmlFormatter extends Formatter { // This method is called for every log records public String format(LogRecord rec) { StringBuffer buf = new StringBuffer(1000); // Bold any levels >= WARNING buf.append("<tr>"); buf.append("<td>"); if (rec.getLevel().intValue() >= Level.WARNING.intValue()) { buf.append("<b>"); buf.append(rec.getLevel()); buf.append("</b>"); } else { buf.append(rec.getLevel()); } buf.append("</td>"); buf.append("<td>"); buf.append(calcDate(rec.getMillis())); buf.append(' '); buf.append(formatMessage(rec)); buf.append('\n'); buf.append("<td>"); buf.append("</tr>\n"); return buf.toString(); } private String calcDate(long millisecs) { SimpleDateFormat date_format = new SimpleDateFormat("MMM dd,yyyy HH:mm"); Date resultdate = new Date(millisecs); return date_format.format(resultdate); } // This method is called just after the handler using this // formatter is created public String getHead(Handler h) { return "<HTML>\n<HEAD>\n" + (new Date()) + "\n</HEAD>\n<BODY>\n<PRE>\n" + "<table width=\"100%\" border>\n " + "<tr><th>Level</th>" + "<th>Time</th>" + "<th>Log Message</th>" + "</tr>\n"; } // This method is called just after the handler using this // formatter is closed public String getTail(Handler h) { return "</table>\n </PRE></BODY>\n</HTML>\n"; } }

Mylogger.java

 package de.vogella.logger; import java.io.IOException; import java.util.logging.FileHandler; import java.util.logging.Formatter; import java.util.logging.Level; import java.util.logging.Logger; import java.util.logging.SimpleFormatter; public class MyLogger { static private FileHandler fileTxt; static private SimpleFormatter formatterTxt; static private FileHandler fileHTML; static private Formatter formatterHTML; static public void setup() throws IOException { // Get the global logger to configure it Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME); logger.setLevel(Level.INFO); fileTxt = new FileHandler("Logging.txt"); fileHTML = new FileHandler("Logging.html"); // Create txt Formatter formatterTxt = new SimpleFormatter(); fileTxt.setFormatter(formatterTxt); logger.addHandler(fileTxt); // Create HTML Formatter formatterHTML = new MyHtmlFormatter(); fileHTML.setFormatter(formatterHTML); logger.addHandler(fileHTML); } }

UseLogger.java

 package de.vogella.logger.test; import java.io.IOException; import java.util.logging.Level; import java.util.logging.Logger; import de.vogella.logger.MyLogger; public class UseLogger { // Always use the classname, this way you can refactor private final static Logger LOGGER = Logger.getLogger(UseLogger.class .getName()); public void doSomeThingAndLog() { // Image here some real work // Now we demo the logging // Set the LogLevel to Severe, only severe Messages will be written LOGGER.setLevel(Level.SEVERE); LOGGER.severe("Info Log"); LOGGER.warning("Info Log"); LOGGER.info("Info Log"); LOGGER.finest("Really not important"); // Set the LogLevel to Info, severe, warning and info will be written // Finest is still not written LOGGER.setLevel(Level.INFO); LOGGER.severe("Info Log"); LOGGER.warning("Info Log"); LOGGER.info("Info Log"); LOGGER.finest("Really not important"); } public static void main(String[] args) { UseLogger tester = new UseLogger(); try { MyLogger.setup(); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException("Problems with creating the log files"); } tester.doSomeThingAndLog(); } }
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1 answer

Change the following line (in the de.vogella.logger.MyLogger.setup() method):

 // Get the global logger to configure it Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);

with:

 // Get the global logger to configure it Logger logger = Logger.getLogger("");

More details:

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Source: https://habr.com/ru/post/945390/

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