Logger entering() method in Java with Examples

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.

  1. 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:

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    // 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()");
        }
    }

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

  2. 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:

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    // 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"));
        }
    }

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    The output printed on log.txt is shown below.

  3. 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:

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    // 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);
        }
    }

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    The output printed on log.txt is shown below.

References:

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