For some reason selenium doesn't locate existing web elements

I'm trying to build a Whatsapp bot in java using selenium and java error I'm working on a function that shows on the screen the response of a recipient that got messaged by the bot earlier.

I found the class "_2wUmf _21bY5 message-in focusable-list-item" to be fitting as it shows incoming messages but when java error I try to search by class name it doesn't find anything, even tried to use css selector but still nothing.

How can I locate those elements and why does it happen?

My code:

import javax.swing.*;  class Main extends JFrame {  public static void main(String[] args) {     new Main(); }  public Main() {     this.setTitle("Whatsapp bot");     this.setLayout(null);     this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);     this.setResizable(false);     this.setSize(Constants.WINDOW_WIDTH, Constants.WINDOW_HEIGHT);     this.add(new MainPanel(0, 0, Constants.WINDOW_WIDTH, Constants.WINDOW_HEIGHT));     this.setVisible(true);  }   } 

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public class Constants { public static final int WINDOW_WIDTH = 1400; public static final int WINDOW_HEIGHT = 800; public static final int LABEL_WIDTH = 110; public static final int LABEL_HEIGHT = 30; public static final int SPACE_BETWEEN_BOXES = 30; public static final int SPACE_BETWEEN_LINES=20; public static final int TEXT_FIELD_WIDTH = 100; public static final int TEXT_FIELD_HEIGHT = 30; public static final int BUTTON_WIDTH = 100; public static final int BUTTON_HEIGHT = 30; public static final int SLEEP_TIME=30; public static final int ONE=1; public static final int TWO=2; public static final int THREE=3; public static final int FOUR=4; public static final int ONE_HUNDRED=100; public static final int MARGIN_FROM_TOP = 10; public static final int MARGIN_FROM_LEFT = 5;  } 

'

import org.openqa.selenium.By; import org.openqa.selenium.NoSuchElementException; import org.openqa.selenium.WebElement; import org.openqa.selenium.chrome.ChromeDriver;  import javax.swing.*; import java.util.List; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicReference;   public class MainPanel extends JPanel { private JButton openWhatsappButton; private JLabel loginSuccessful; private JTextField enterPhone; private JTextField enterMessage; private JLabel enterPhoneLabel; private JLabel enterMessageLabel; private JLabel whyIsThePhoneEmptyLabelOrInvalid; private JLabel whyIsTheMessageEmptyLabel; private JLabel messageSentLabel; private JLabel messageReadOrDeliveredLabel; private JLabel responseLabel;  public String phoneNumberFormatValidationAndReformation(String givenPhoneNumber) {     String ans = new String();     final int CORRECT_LENGTH_VERSION_A = 12;     final String CORRECT_START_OF_PHONE_NUMBER_VERSION_A = "9725";     final int START = 0;     final int END_VERSION_A = 4;     final int CORRECT_LENGTH_VERSION_B = 10;     final String CORRECT_START_OF_PHONE_NUMBER_VERSION_B = "05";     final int END_VERSION_B = 2;     final int START_OF_REFORMATTED_VERSION_B_ORIGIN = 2;     if ((CORRECT_LENGTH_VERSION_A == givenPhoneNumber.length()) && (CORRECT_START_OF_PHONE_NUMBER_VERSION_A.equals(givenPhoneNumber.substring(START, END_VERSION_A)))) {         ans = givenPhoneNumber;     }     if ((CORRECT_LENGTH_VERSION_B == givenPhoneNumber.length()) && (CORRECT_START_OF_PHONE_NUMBER_VERSION_B.equals(givenPhoneNumber.substring(START, END_VERSION_B)))) {         ans = CORRECT_START_OF_PHONE_NUMBER_VERSION_A + givenPhoneNumber.substring(START_OF_REFORMATTED_VERSION_B_ORIGIN);     }     return ans; }  public MainPanel(int x, int y, int width, int height) {     this.setLayout(null);     this.setBounds(x, y, width, height);     System.setProperty("webdriver.chrome.driver", "C:\\Users\\danie\\OneDrive\\Desktop\\chromedriver.exe");     ChromeDriver driver = new ChromeDriver();     driver.manage().window().minimize();     openWhatsappButton = new JButton("Send");     openWhatsappButton.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.BUTTON_WIDTH / Constants.TWO, Constants.WINDOW_HEIGHT / Constants.TWO - Constants.BUTTON_HEIGHT / Constants.TWO, Constants.BUTTON_WIDTH, Constants.BUTTON_HEIGHT);     this.add(openWhatsappButton);     loginSuccessful = new JLabel("Logged in successfully!");      enterPhone = new JTextField();     enterPhone.setBounds(Constants.WINDOW_WIDTH / Constants.FOUR - Constants.TEXT_FIELD_WIDTH, Constants.WINDOW_HEIGHT / Constants.TWO - Constants.SPACE_BETWEEN_LINES * Constants.FOUR, Constants.TEXT_FIELD_WIDTH * Constants.TWO, Constants.TEXT_FIELD_HEIGHT);     this.add(enterPhone);     enterPhoneLabel = new JLabel("Enter a phone number: ");     enterPhoneLabel.setBounds(enterPhone.getX() - Constants.ONE - Constants.FOUR * Constants.LABEL_WIDTH / Constants.THREE, enterPhone.getY(), Constants.FOUR * Constants.LABEL_WIDTH / Constants.THREE, Constants.LABEL_HEIGHT);     this.add(enterPhoneLabel);     whyIsThePhoneEmptyLabelOrInvalid = new JLabel("~You must enter a number...");     whyIsThePhoneEmptyLabelOrInvalid.setBounds(enterPhone.getX() + Constants.ONE + Constants.TEXT_FIELD_WIDTH * Constants.TWO, enterPhone.getY(), Constants.FOUR * Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);     enterMessage = new JTextField();     enterMessage.setBounds(Constants.THREE * Constants.WINDOW_WIDTH / Constants.FOUR - Constants.TEXT_FIELD_WIDTH, Constants.WINDOW_HEIGHT / Constants.TWO - Constants.SPACE_BETWEEN_LINES * Constants.FOUR, Constants.TEXT_FIELD_WIDTH * Constants.TWO, Constants.TEXT_FIELD_HEIGHT);     this.add(enterMessage);     enterMessageLabel = new JLabel("Enter a message: ");     enterMessageLabel.setBounds(enterMessage.getX() - Constants.ONE - Constants.LABEL_WIDTH, enterMessage.getY(), Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);     this.add(enterMessageLabel);     whyIsTheMessageEmptyLabel = new JLabel("~You must enter a message...");     whyIsTheMessageEmptyLabel.setBounds(enterMessage.getX() + Constants.ONE + Constants.TEXT_FIELD_WIDTH * Constants.TWO, enterMessage.getY(), Constants.TWO * Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);     loginSuccessful.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.LABEL_WIDTH, openWhatsappButton.getY() - Constants.TWO * Constants.SPACE_BETWEEN_LINES, Constants.TWO * Constants.LABEL_WIDTH, Constants.BUTTON_HEIGHT);     messageSentLabel = new JLabel("Message sent");     messageSentLabel.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.LABEL_WIDTH / Constants.TWO, openWhatsappButton.getY() + Constants.TWO * Constants.SPACE_BETWEEN_LINES, Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);     messageReadOrDeliveredLabel = new JLabel("Message has been delivered");     messageReadOrDeliveredLabel.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.LABEL_WIDTH, messageSentLabel.getY() + Constants.TWO * Constants.SPACE_BETWEEN_LINES, Constants.TWO * Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);     responseLabel = new JLabel("No response yet");     responseLabel.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.LABEL_WIDTH, messageSentLabel.getY() + Constants.FOUR * Constants.SPACE_BETWEEN_LINES, Constants.TWO * Constants.LABEL_WIDTH, Constants.LABEL_HEIGHT);      openWhatsappButton.addActionListener(e -> {         boolean toBraek = false;         List<WebElement> messagesDoubleChecksBefore = null;         boolean toContinue = true;         if (enterMessage.getText().equals("") || enterMessage.getText() == null) {             whyIsTheMessageEmptyLabel.setText("~You must enter a message...");             this.add(whyIsTheMessageEmptyLabel);             repaint();             toContinue = false;         } else {             whyIsTheMessageEmptyLabel.setText("");             repaint();         }         String phoneNumber = phoneNumberFormatValidationAndReformation(enterPhone.getText());         if (enterPhone.getText().equals("") || enterPhone.getText() == null) {             whyIsThePhoneEmptyLabelOrInvalid.setText("~You must enter a number...");             this.add(whyIsThePhoneEmptyLabelOrInvalid);             repaint();             toContinue = false;         } else {             if (phoneNumber.equals("") || phoneNumber == null) {                 whyIsThePhoneEmptyLabelOrInvalid.setText("~phone number invalid");                 this.add(whyIsThePhoneEmptyLabelOrInvalid);                 repaint();                 toContinue = false;             }         }         if (toContinue) {             driver.get("https://web.whatsapp.com/send?phone=" + phoneNumber);             driver.manage().window().maximize();              try {                 Thread.sleep(Constants.SLEEP_TIME);             } catch (InterruptedException ex) {                 ex.printStackTrace();             }              boolean loggedIn = false;             while (true) {                 if (!loggedIn) {                     try {                          if (driver.findElement(By.id("pane-side")).isEnabled()) {                              this.add(loginSuccessful);                             repaint();                             loggedIn = true;                         } else {                             continue;                         }                      } catch (NoSuchElementException exception) {                         continue;                     }                 }                 if (loggedIn) {                     boolean triedToSend = false;                     try {                         if (driver.findElement(By.cssSelector("div[ title=\"loading messages…\"]")).isEnabled()) {                             System.out.println("massage loading");                             continue;                         }                     } catch (NoSuchElementException exception) {                      }                     List<WebElement> messagesChecksBefore = null;                     try {                         System.out.println("message not loading anymore");                           messagesDoubleChecksBefore = driver.findElements(By.cssSelector("span[data-icon='msg-dblcheck']"));                         messagesChecksBefore = driver.findElements(By.cssSelector("span[data-icon='msg-dblcheck']"));                         messagesChecksBefore.addAll(driver.findElements(By.cssSelector("span[data-icon='msg-check']")));                         messagesChecksBefore.addAll(driver.findElements(By.cssSelector("span[data-icon='msg-time']")));                         System.out.println(messagesChecksBefore.size());                     } catch (NoSuchElementException exception) {                     }                     try {                         Thread.sleep(Constants.SLEEP_TIME);                     } catch (InterruptedException ex) {                         ex.printStackTrace();                     }                     try {                         WebElement typingBox = driver.findElement(By.xpath("/html/body/div[1]/div/div/div[4]/div/footer/div[1]/div/span[2]/div/div[2]/div[1]/div/div[2]"));                         typingBox.sendKeys(enterMessage.getText());                         driver.findElement(By.xpath("/html/body/div[1]/div/div/div[4]/div/footer/div[1]/div/span[2]/div/div[2]/div[2]/button/span")).click();                         triedToSend = true;                     } catch (NoSuchElementException exception) {                     }                     try {                         Thread.sleep(Constants.ONE_HUNDRED * Constants.SLEEP_TIME);                     } catch (InterruptedException ex) {                         ex.printStackTrace();                     }                     List<WebElement> messagesChecksAfter = null;                     try {                         messagesChecksAfter = driver.findElements(By.cssSelector("span[data-icon='msg-dblcheck']"));                         messagesChecksAfter.addAll(driver.findElements(By.cssSelector("span[data-icon='msg-check']")));                         messagesChecksAfter.addAll(driver.findElements(By.cssSelector("span[data-icon='msg-time']")));                         System.out.println(messagesChecksAfter.size());                     } catch (NoSuchElementException exception) {                     }                     if (messagesChecksAfter.size() == Constants.ONE + messagesChecksBefore.size() && triedToSend) {                         this.add(messageSentLabel);                         repaint();                         System.out.println("should paint the message sent label");                         toBraek = true;                     }                       if (toBraek) {                         break;                     } else {                         System.out.println("reattempting to send...");                     }                  }              }             AtomicReference<List<WebElement>> messagesInTimeOfReading = null;             List<WebElement> effectivelyFinalMessagesDoubleChecksBefore = messagesDoubleChecksBefore;             AtomicBoolean threadClosed = new AtomicBoolean(false);             new Thread(() -> {                 while (true) {                     System.out.println("loops in thread");                     List<WebElement> messagesDoubleChecksAfter = null;                     boolean toBreakThatLoop = false;                     try {                         messagesDoubleChecksAfter = driver.findElements(By.cssSelector("span[data-icon='msg-dblcheck']"));                     } catch (NoSuchElementException exception) {                      }                     if (messagesDoubleChecksAfter.size() > effectivelyFinalMessagesDoubleChecksBefore.size()) {                         toBreakThatLoop = true;                         WebElement lastDoubleCheck = messagesDoubleChecksAfter.get(messagesDoubleChecksAfter.size() - Constants.ONE);                         while (true) {                             if (lastDoubleCheck.getAccessibleName().equals("Read ") || lastDoubleCheck.getAccessibleName().equals("Read")) {                                 messageReadOrDeliveredLabel.setText("Message has been read");                                 this.add(messageReadOrDeliveredLabel);                                 repaint();                                 System.out.println("message was read");                                 try {                                     messagesInTimeOfReading.set(driver.findElements(By.cssSelector("div[ class='_2wUmf _21bY5 message-in focusable-list-item']")));                                 } catch (NoSuchElementException exception){                                  } catch (NullPointerException exception2) {                                  }                                 try{                                 messagesInTimeOfReading.get().addAll(driver.findElements(By.cssSelector("div[class='_2wUmf.message-in.focusable-list-item']")));                                 } catch (NoSuchElementException exception){                                  } catch (NullPointerException exception2) {                                  }                                 break;                             } else {                                 messageReadOrDeliveredLabel.setText("Message has been delivered");                                 this.add(messageReadOrDeliveredLabel);                                 repaint();                             }                         }                         if (toBreakThatLoop) {                             break;                         }                     } else {                         try {                             Thread.sleep(Constants.SLEEP_TIME);                         } catch (InterruptedException ex) {                             ex.printStackTrace();                         }                     }                  }                 threadClosed.set(true);             }).start();             this.add(responseLabel);             int messagesInTimeOfReadingCount=0;             messagesInTimeOfReading.get().size();             if (messagesInTimeOfReading!=null){                 messagesInTimeOfReadingCount=messagesInTimeOfReading.get().size();                 System.out.println("found incoming messages");             }             int effectivelyFinalMessagesInTimeOfReadingCount = messagesInTimeOfReadingCount;             new Thread(() -> {                 while (true) {                     if (threadClosed.get()) {                         List<WebElement> currentMessages = null;                         try {                             currentMessages=(driver.findElements(By.cssSelector("div[ class='_2wUmf _21bY5 message-in focusable-list-item']")));                         } catch (NoSuchElementException exception){                          } catch (NullPointerException exception2) {                          }                         try{                             currentMessages.addAll(driver.findElements(By.cssSelector("div[class='_2wUmf.message-in.focusable-list-item']")));                         } catch (NoSuchElementException exception){                          } catch (NullPointerException exception2) {                          }                         int currentMessagesCount=0;                          if (currentMessages!=null){                             currentMessagesCount=currentMessages.size();                         }                         if (currentMessagesCount > effectivelyFinalMessagesInTimeOfReadingCount) {                             WebElement response = currentMessages.get(currentMessages.size() - Constants.ONE);                             String printToResponseLabel = "Response: " + response.getAccessibleName();                             int textLength = printToResponseLabel.length();                             responseLabel.setBounds(Constants.WINDOW_WIDTH / Constants.TWO - Constants.TWO * textLength, messageSentLabel.getY() + Constants.FOUR * Constants.SPACE_BETWEEN_LINES, Constants.FOUR * textLength, Constants.LABEL_HEIGHT);                             responseLabel.setText(printToResponseLabel);                             repaint();                             break;                         }                     }                 }             }).start();         }     });   }  } 

Answers 1: of For some reason selenium doesn't locate existing web elements