Can you explain what am I doing wrong?

Question about the task

Adding logging to a class

Java Collections, Level 4, Lesson 10

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I don't get this task, please help

In Intellij IDEA, press Alt+Ctrl+Shift+S -> Global Libraries -> New Global Library -> From Maven...
In the window that opens, enter the following in the search bar: org.slf4j:slf4j-api:1.7.23 -> Search (Shift+Enter)
Choose where to download the logging library.
Choose the project module you want to connect the slf4j-api library to: you need to select
4.JavaCollections -> OK
Apply -> OK.

Look in the Solution class. Where would you apply logging and at what level?

In the Solution class, you need to add method calls at the following log levels:
error - 1 time;
debug - 6 times (use when changing the value of a field);
trace - 4 times (use to trace the execution of a program);
Try to make the log messages informative.
Don't change the rest of the code.

Requirements:

There must be a private static final logger field in the Solution class.
Add the error log level once.
Add the debug log level six times.
Add the trace log level four times.

package com.codegym.task.task34.task3412; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Date; public class Solution { private static final Logger logger = LoggerFactory.getLogger(Solution.class); private int value1; private String value2; private Date value3; public Solution(int value1, String value2, Date value3) { this.value1 = value1; this.value2 = value2; this.value3 = value3; } public static void main(String[] args) { } public void calculateAndSetValue3(long value) { value -= 133; if (value > Integer.MAX_VALUE) { value1 = (int) (value / Integer.MAX_VALUE); } else { value1 = (int) value; } } public void printString() { if (value2 != null) { logger.warn("Some Warn"); logger.warn("Some Warn"); logger.warn("Some Warn"); logger.warn("Some Warn"); System.out.println(value2.length()); } } public void printDateAsLong() { logger.debug("SomeDebug"); logger.debug("SomeDebug"); logger.debug("SomeDebug"); logger.debug("SomeDebug"); logger.debug("SomeDebug"); logger.debug("SomeDebug"); if (value3 != null) { System.out.println(value3.getTime()); } } public void divide(int number1, int number2) { try { System.out.println(number1 / number2); } catch (ArithmeticException e) { logger.error("ArithExc", e); } } public void setValue1(int value1) { this.value1 = value1; } public void setValue2(String value2) { this.value2 = value2; } public void setValue3(Date value3) { this.value3 = value3; } }

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Wei Cui

Level 39 , Newark, United States

15 April 2020, 03:06

solution

error - 1 time; debug - 6 times (use when changing the value of a field); trace - 4 times (use to trace the execution of a program);

public Solution(int value1, String value2, Date value3) {
       logger.debug("Constructor 1:"+this.value1+" 2: "+this.value2+" 3: "+this.value3);
       this.value1 = value1;
       this.value2 = value2;
       this.value3 = value3;
   }

   public static void main(String[] args) {

   }

   public void calculateAndSetValue3(long value) {
       logger.trace("start calculateAndSetValue3");
       value -= 133;
       if (value > Integer.MAX_VALUE) {
           value1 = (int) (value / Integer.MAX_VALUE);
           logger.debug("New value1:"+value1);
       } else {
           value1 = (int) value;
           logger.debug("new Value1 " + value1);
       }

   }

   public void printString() {
       logger.trace("printString");
       if (value2 != null) {
           System.out.println(value2.length());

       }

   }

   public void printDateAsLong() {
       logger.trace ("Start printDateAsLong");
       if (value3 != null) {
           System.out.println(value3.getTime());
       }
   }

   public void divide(int number1, int number2) {
       logger.trace ("Start divide");
       try {
           System.out.println(number1 / number2);
       } catch (ArithmeticException e) {
           logger.error("Error: " + e);
       }
   }

   public void setValue1(int value1) {
       logger.debug("setValue1:"+value1);
       this.value1 = value1;
   }

   public void setValue2(String value2) {
       logger.debug("setValue2:"+value2);
       this.value2 = value2;
   }

   public void setValue3(Date value3) {
       logger.debug("setValue3:"+value3.toString());
       this.value3 = value3;
   }

Jonas

Level 41 , Vilnius, Lithuania

15 April 2020, 14:30

Hello, thanks for help, but it says that my Logger object doesn't have method logger.trace() it says that I have to create Logger object based on org.apache.log4j.Logger class and not based on org.slf4j.LoggerFactory could you please share your solution? Thank you

Wei Cui

Level 39 , Newark, United States

15 April 2020, 14:51

useful

i supposed you not import Logger correctly, following the instruction: In Intellij IDEA, press Alt+Ctrl+Shift+S -> Global Libraries -> New Global Library -> From Maven... In the window that opens, enter the following in the search bar: org.slf4j:slf4j-api:1.7.23 -> Search (Shift+Enter) Choose where to download the logging library. Choose the project module you want to connect the slf4j-api library to: you need to select 4.JavaCollections -> OK Apply -> OK. here is my whole code

package com.codegym.task.task34.task3412;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;

/*
Adding logging to a class

*/

public class Solution {
    private static final Logger logger = LoggerFactory.getLogger(Solution.class);

    private int value1;
    private String value2;
    private Date value3;

    public Solution(int value1, String value2, Date value3) {
        logger.debug("Constructor 1:"+this.value1+" 2: "+this.value2+" 3: "+this.value3);
        this.value1 = value1;
        this.value2 = value2;
        this.value3 = value3;
    }

    public static void main(String[] args) {

    }

    public void calculateAndSetValue3(long value) {....}

Jonas

Level 41 , Vilnius, Lithuania

16 April 2020, 06:05

I did everything like codegym said, but I can't access trace method, tho I can access debug and error methods. Weirdness.

Jonas

Level 41 , Vilnius, Lithuania

16 April 2020, 06:11

Oh, I found my mistake. I had org.slf4j:slf4j-api:1.7.23 library set as a global one, but I also had another library, that I downloaded from internet, set as non global library, so when I was trying to get a new Logger object it would access non global library(which didn't have trace method), so when I removed the non-global library it worked. Thanks for help.