Question

Do we have any Debug viewer free tool for Java that we use for .net (microsoft)?

If we write Debug.Writeline(“Hello World”); that will print line in DebugView v4.78 tool.

I am trying to find that Java code also should print. Any tool available for java?

Answer 1

Discover log4j! Log4J is a logging library for Java, it will provide you with an ability to configure where to save log statements via different loggers.

For example, you can configure log4j to store all your log statements done via general-purpose logger into file normal.log, and log statements done via dedicated logger into file very-special-errors.log. If you want real-time monitoring and you on Unix, just say tail -f very-special-errors.log.

Here’s sample log4j.properties file for that purpose:

log4j.rootLogger=DEBUG, R
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=normal.log

log4j.appender.R.MaxFileSize=100KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1

log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n

log4j.logger.specialLogger=ERROR, errorAppender
log4j.additivity.specialLogger=false
log4j.appender.errorAppender=org.apache.log4j.RollingFileAppender
log4j.appender.errorAppender.File=very-special-errors.log

log4j.appender.errorAppender.MaxFileSize=100KB
# Keep one backup file
log4j.appender.errorAppender.MaxBackupIndex=1

log4j.appender.errorAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.errorAppender.layout.ConversionPattern=%p %t %c - %m%n

and here’s sample Java code which uses this setup

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class Main {
    private static final Logger normalLog = Logger.getLogger("rootLogger");
    private static final Logger specialLogger = Logger.getLogger("specialLogger");

    public static void main(String[] args) {
        PropertyConfigurator.configure("log4j.properties");
        normalLog.info("Normal info");
        specialLogger.info("Special info -- won't be logged due to min logging level for specialLogger");
        specialLogger.error("Special error -- will be logged");
    }
}