Jakarta Mail throws: Not provider of jakarta.mail.util.StreamProvider was found

I am new to Jakarta Mail and trying out a standalone test program but I am get the following error

Exception in thread “main” java.lang.IllegalStateException: Not provider of jakarta.mail.util.StreamProvider

I use the following to run at the command line in Windows

C:Progra~1Javajdk-21binjava -classpath .;jakarta.mail-api-2.1.0.jar;jakarta.activation-api-2.1.2.jar TestEmail

The program is a simple one I copied from internet.

I compiled using the following on the command line

C:Progra~1Javajdk-21binjavac -classpath .;jakarta.mail-api-2.1.0.jar;jakarta.activation-api-2.1.2.jar TestEmail.java

import jakarta.mail.*;
import jakarta.mail.internet.*;

import java.time.*;
import java.util.*;

public class TestEmail {
     public static void main(String[] args) {

        
        String to = "sendToMailAddress";
        String from = "sendFromMailAddress";
        
        String host = "smtp.yourisp.invalid";

        // Create properties, get Session
        Properties props = new Properties();

Any help will be much appreciated.
Peter

Remove api jar

jakarta.mail-api-2.1.0.jar
jakarta.activation-api-2.1.2.jar

Because the official jakarta mail api does not provide complete implementation.

just use this one: com.sun.mail:jakarta.mail:2.0.1

is enough.

Download Implementation jar

Maven

pom.xml

<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>jakarta.mail</artifactId>
    <version>2.0.1</version>
</dependency>

or download only 2 files:

jakarta.mail-2.0.1.jar (https://repo1.maven.org/maven2/com/sun/mail/jakarta.mail/2.0.1/jakarta.mail-2.0.1.jar)
jakarta.activation-2.0.1.jar (https://repo1.maven.org/maven2/com/sun/activation/jakarta.activation/2.0.1/jakarta.activation-2.0.1.jar)

your javac

C:Progra~1Javajdk-21binjavac -classpath .;jakarta.mail-2.0.1.jar;jakarta.activation-2.0.1.jar TestEmail.java

run

C:Progra~1Javajdk-21binjava -classpath .;jakarta.mail-2.0.1.jar;jakarta.activation-2.0.1.jar TestEmail

Update – NOTE

Why do some answers tell us to add jakarta.mail-api and some answers tell us to add com.sun.mail:jakarta.mail?

If you are developing Jakarta Web (war), then add the following:

<dependency>
    <groupId>jakarta.mail</groupId>
    <artifactId>jakarta.mail-api</artifactId>
    <version>2.1.3</version>
</dependency>

Run command:

mvn dependency:tree

get result:

[INFO] - jakarta.mail:jakarta.mail-api:jar:2.1.3:compile
[INFO]    - jakarta.activation:jakarta.activation-api:jar:2.1.3:compile

then build

mvn clean package

get hello.war (my example)

Test On Server: wildfly-33.0.1.Final

wildfly provides a complete Jakarta EE Server implementation (including mail), so only adding the above dependent content can send emails.

Test On Server: apache-tomcat-10.1.28

Tomcat does not provide a complete Jakarta EE Server implementation, so adding only the above dependencies will result in an error message:

No provider of jakarta.mail.util.StreamProvider was found</p><p><b>Description</b> The server encountered an unexpected condition that prevented it from fulfilling the request.</p><p><b>Exception</b></p><pre>java.lang.IllegalStateException: No provider of jakarta.mail.util.StreamProvider was found
    jakarta.mail.util.FactoryFinder.find(FactoryFinder.java:61)
    jakarta.mail.util.StreamProvider.provider(StreamProvider.java:199)
    jakarta.mail.Session.<init>(Session.java:257)
    jakarta.mail.Session.getInstance(Session.java:310)
    com.example.HelloMailServlet.doGet(HelloMailServlet.java:40)
    jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
    jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:5

Therefore, the same war file will have different results when deployed to Wildfly and Tomcat. Tomcat does not provide a complete Jakarta EE implementation, so some implementations are often missing. Therefore, we need to add additional implementations. library for tomcat war.

Since Java Application is not a Jakarta EE Server, it naturally does not have an implementation of Jakarta EE, so we directly use the jar that implements jakarta mail.

<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>jakarta.mail</artifactId>
    <version>2.0.1</version>
</dependency>

(The War file deployed to Tomcat is also changed to add this Jar.)

in conclusion:

If your program is to be deployed in an environment with a complete Jakarta EE implementation (Wildfly Server),

please add:

<dependency>
    <groupId>jakarta.mail</groupId>
    <artifactId>jakarta.mail-api</artifactId>
    <version>2.1.3</version>
</dependency>

If your program is intended for use without a complete Jakarta EE implementation (Standalone Java Application, Tomcat Server),