Sending picture through an email with JavaMailAPI

Question

I am using JavaMailAPI and I want to send an email with attachments (either PDF or photos). Currently, I am just displaying picture taken on imageView but when I press button, imageView should be cleaned and email should be sent.

private static final int PERMISSION_CODE = 1000;
private static final int IMAGE_CAPTURE_CODE = 1001;

Button buttonOpenCamera, buttonSendEmail;
ImageView imageView;
Uri image_uri;
EditText mRecipientEt, mSubjectEt, mMessageEt, mDocumentNumber;


buttonSendEmail.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        sendEmail();
    }
});


private void sendEmail() {
    String subject = mSubjectEt.getText().toString().trim();
    String mail = mRecipientEt.getText().toString().trim();
    String message = mMessageEt.getText().toString().trim();

    JavaMailAPI javaMailAPI = new JavaMailAPI(this, mail, subject, message);
    javaMailAPI.execute();
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

    if (resultCode == RESULT_OK) {
        try {
            imageView.setImageURI(image_uri);
        } catch (Exception e) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        }
    }
}