Logger entering() method in Java with Examples

Last Updated : 28 Mar, 2019

The entering() method of a Logger class used to Log a method entry.
There are three types of entering() method depending upon the parameters passed.

entering(String sourceClass, String sourceMethod): This method is used to Log a method entry.Actually many times in application development we need to log when we enter in a method of class so this is a convenience method that can be used to log entry to a method. This method logs with message "ENTRY", log level FINER, and the given sourceMethod and sourceClass are also logged. Syntax:

public void entering(String sourceClass,
                     String sourceMethod)

Parameters: This method accepts two parameters:

sourceClass is the name of the class that issued the logging request and
sourceMethod is the name of the method that is being entered.

Return value: This method returns nothing. Below program illustrate entering(String sourceClass, String sourceMethod) method: Program 1:

Java

// Java program to demonstrate
// entering(String, String) method

import java.io.IOException;
import java.util.List;
import java.util.logging.*;

public class GFG {

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

        // Create a Logger
        Logger logger
            = Logger.getLogger(
                GFG.class.getName());

        // Create a file handler object
        FileHandler handler
            = new FileHandler("logs.txt");
        handler.setFormatter(new SimpleFormatter());

        // Add file handler as
        // handler of logs
        logger.addHandler(handler);

        // set Logger level()
        logger.setLevel(Level.FINER);

        // call entering methods with class
        // name =  GFG and method name = main
        logger.entering(GFG.class.getName(), "main");

        // calling again for List class toString()
        logger.entering(List.class.getName(), "toString()");
    }
}

The output printed on log.txg file is shown below. Output:

entering(String sourceClass, String sourceMethod, Object param1): This method is used to Log a method entry, with one parameter where parameter passed is an object we want to log. Actually many times in application development we need to log when we enter in a method of class so this is a convenience method that can be used to log entry to a method. This method logs with message "ENTRY {0}", log level FINER, and the given sourceMethod, sourceClass, and parameter are logged. Syntax:

public void entering(String sourceClass,
                     String sourceMethod,
                     Object param1)

Parameters: This method accepts three parameters:

sourceClass is the name of the class that issued the logging request and
sourceMethod is the name of the method that is being entered.
param1: is the parameter to the method being entered.

Return value: This method returns nothing. Below programs illustrate entering(String sourceClass, String sourceMethod, Object param1) method: Program 1:

Java

// Java program to demonstrate
// entering(String, String, Object) method

import java.io.IOException;
import java.util.logging.*;

public class GFG {

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

        // Create a Logger
        Logger logger
            = Logger.getLogger(
                GFG.class.getName());

        // Create a file handler object
        FileHandler handler
            = new FileHandler("logs.txt");
        handler.setFormatter(new SimpleFormatter());

        // Add file handler as
        // handler of logs
        logger.addHandler(handler);

        // set Logger level()
        logger.setLevel(Level.FINER);

        // call entering method with class
        // name =  GFG and method name = main
        logger.entering(
            GFG.class.getName(), "main",
            new String("Java is Platform Independent"));
    }
}

The output printed on log.txt is shown below.

entering(String sourceClass, String sourceMethod, Object[] params): This method is used to Log a method entry, with an array of parameters. Actually many times in application development we need to log when we enter in a method of class so this is a convenience method that can be used to log entry to a method. This method logs with message "ENTRY" (followed by a format {N} indicator for each entry in the parameter array), log level FINER, and the given sourceMethod, sourceClass, and parameter are logged. Syntax:

public void entering(String sourceClass,
                     String sourceMethod,
                     Object[] params)

Parameters: This method accepts three parameters:

sourceClass is the name of the class that issued the logging request and
sourceMethod is the name of the method that is being entered.
params: is an array of parameters to the method being entered.

Return value: This method returns nothing. Below programs illustrate entering(String sourceClass, String sourceMethod, Object[] params) method: Program 1:

Java

// Java program to demonstrate
// entering(String, String, Object[])  method

import java.io.IOException;
import java.util.logging.*;

public class GFG {

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

        // Create a Logger
        Logger logger
            = Logger.getLogger(
                GFG.class.getName());

        // Create a file handler object
        FileHandler handler
            = new FileHandler("logs.txt");
        handler.setFormatter(new SimpleFormatter());

        // Add file handler as
        // handler of logs
        logger.addHandler(handler);

        // set Logger level()
        logger.setLevel(Level.FINER);

        // create a array of String object
        String[] methods = {
            "main", "ADD", "get", "set"
        };

        // call entering method with class
        // name =  GFG and method name = main
        logger.entering(GFG.class.getName(), "main",
                        methods);
    }
}