private void sendEmail(String from, String to, String subject, String text, boolean isHtml) {
        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        try {
            MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, "utf-8");
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(text, isHtml);
            javaMailSender.send(mimeMessage);
        } catch (MessagingException e) {
            LOG.error("message send error", e);
        }
    }

<bean id="javaMailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
        <property name="host" value="smtp.yandex.ru"/>
        <property name="port" value="465"/>
        <property name="protocol" value="smtp"/>
        <property name="username" value="****"/>
        <property name="password" value="****"/>
        <property name="javaMailProperties">
            <props>
                <prop key="mail.smtp.auth">true</prop>
                <prop key="mail.smtp.starttls.enable">false</prop>
                <prop key="mail.smtp.quitwait">false</prop>
                <prop key="mail.smtp.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
                <prop key="mail.smtp.socketFactory.fallback">false</prop>
                <prop key="mail.debug">true</prop>
            </props>
        </property>
    </bean>

System.setProperty("mail.mime.charset", "utf-8");
mimeMessage.setContent(message, "text/html; charset=utf-8");

<property name="defaultEncoding" value="utf-8"/>