How to print log statements in a single line using Log4J?

Question

I have a maven application which contains the logger configured as below.

import org.apache.commons.cli.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class StartCount {
    public static void main(String[] args) throws Exception {
        ChunkRecon chRecon;
        Options options = new Options();
        Option input    = new Option("s", "ssn", true, "source system names");
        input.setRequired(false);
        options.addOption(input);
        CommandLineParser parser = new DefaultParser();
        HelpFormatter formatter  = new HelpFormatter();
        CommandLine cmd          = null;
        CustomSsnTableRecon cstr;
        final Logger LOGGER = Logger.getLogger(StartCount.class.getName());
        try {
            cmd = parser.parse(options, args);
            if(cmd.hasOption("s")) {            // Checks if there is an argument '--s' in the CLI.
                String sources = cmd.getOptionValue("s");
                if(sources == null) {
                    System.out.println("Please enter a source system name using the option '--s' and submit the jar again.. Ex: --s ABC ");
                    System.exit(1);
                }
                if(sources.contains("custom")) {
                    cstr = new CustomSsnTableRecon(sources);
                    cstr.getChunks();
                    cstr.reconDataFile();
                } else {
                    LOGGER.log(Level.INFO, "Starting recon for the source: " + sources);
                    chRecon = new ChunkRecon(sources);
                    chRecon.getChunks();
                    chRecon.reconDataFile();
                }
            } else {
                LOGGER.log(Level.WARNING, "Please enter a source system using the option '--s' and submit the jar again. Ex: --s ABC");
                System.out.println("Please enter a source system name using the option '--s' and submit the jar again.. Ex: --s ABC ");
                System.exit(1);
            }
        } catch(ParseException e) {
            LOGGER.log(Level.WARNING, "Please enter a source system using the option '--s' and submit the jar again. Ex: --s ABC");
            formatter.printHelp("utility-name", options);
            e.printStackTrace();
            System.exit(1);
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
}

This is my logger.properties file:

log4j.rootLogger=DEBUG, INFO, WARN, ERROR, stdout, file

# Redirect log messages to console
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

When I run the program I don't see any errors and the logs are coming out fine. But they are being printed in two lines as shown below:

Nov 18, 2019 12:30:22 PM com.recordcount.entry.StartCount main
INFO: Starting recon for the source: GCORP_HFM

Project Structure:

Is there any way I can print the log in a single statement & also can we print just the class name instead of full package & class name:

Nov 18, 2019 12:30:22 PM StartCount main INFO: Starting recon for the source: GCORP_HFM

Answer 1

You can alter the pattern of your logger with ConversionPatterns in the settings of Log4J: https://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/PatternLayout.html This helps you achieve more customized log messages and you can experiment with what the options are and what you would like to see.

Answer 2

1. Rename your log properties file from 'logger.properties' to 'log4j.properties'.
2. To output only class name use %C{1} instead of %c{1} .