SEVERE: ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer in Tomcat deployment

[PriyaFf]

I am working on a Java web application and deploying it on Apache Tomcat.

When I try to start the server, I get the following error:
SEVERE: Servlet [jersey-servlet] in web application [/Projectname] threw load() exception
java.lang.ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer

I have configured my web.xml as follows:

<servlet>
    <servlet-name>jersey-servlet</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>jersey.config.server.provider.packages</param-name>
        <param-value>com.myapp.rest</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>jersey-servlet</servlet-name>
    <url-pattern>/api/*</url-pattern>
</servlet-mapping>
I am not using Maven, and I copied the required .jar files manually.

⚠️ My Questions:
Why is this class org.glassfish.jersey.servlet.ServletContainer not found?

Which .jar file contains this class?

Where should I place the JAR file in a non-Maven Tomcat project?

🔧 My environment:
Java version: 21

Tomcat version: 10.0.27

IDE: Eclipse 4.35

Project Type: Non-Maven Dynamic Web Project

[jbescos]

Hi, you will need at least these dependencies (modify the version accordingly):

[INFO] org.glassfish.jersey.containers:jersey-container-servlet-core:jar:3.1.99-SNAPSHOT
[INFO] +- jakarta.inject:jakarta.inject-api:jar:2.0.1:compile
[INFO] +- org.glassfish.jersey.core:jersey-common:jar:3.1.99-SNAPSHOT:compile
[INFO] +- org.glassfish.jersey.core:jersey-server:jar:3.1.99-SNAPSHOT:compile
[INFO] +- jakarta.ws.rs:jakarta.ws.rs-api:jar:3.1.0:compile

[jansupol]

org.glassfish.jersey.servlet.ServletContainer is in jersey-container-servlet-core.
For additional Servlet 3.1 features, jersey-container-servlet is required.

[jbescos]

Right, I thought it was in org.glassfish.jersey.core:jersey-server. I have updated my previous comment.

[PriyaFf]

I add these jars. But still I got same SEVERE: Servlet [jersey-servlet] in web application [/FenfeoWebServiceTest] threw load() exception java.lang.ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer

…

________________________________ From: Jorge Bescos Gascon ***@***.***> Sent: Wednesday, July 23, 2025 12:16 To: eclipse-ee4j/jersey ***@***.***> Cc: PriyaFf ***@***.***>; Author ***@***.***> Subject: Re: [eclipse-ee4j/jersey] SEVERE: ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer in Tomcat deployment (Discussion #5956) Hi, you will need at least these dependencies (modify the version accordingly): [INFO] org.glassfish.jersey.core:jersey-server:jar:2.48-SNAPSHOT [INFO] +- org.glassfish.jersey.core:jersey-common:jar:2.48-SNAPSHOT:compile [INFO] +- org.glassfish.jersey.core:jersey-client:jar:2.48-SNAPSHOT:compile [INFO] +- jakarta.ws.rs:jakarta.ws.rs-api:jar:2.1.6:compile [INFO] +- jakarta.annotation:jakarta.annotation-api:jar:1.3.5:compile [INFO] +- org.glassfish.hk2.external:jakarta.inject:jar:2.6.1:compile [INFO] +- jakarta.validation:jakarta.validation-api:jar:2.0.2:compile — Reply to this email directly, view it on GitHub<#5956 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BDF7JWGJTINARV7BPBTVSQD3J4VUBAVCNFSM6AAAAACCE3ETO6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOBVHE2DAOI>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[jbescos]

Did you add this dependency?: https://mvnrepository.com/artifact/org.glassfish.jersey.containers/jersey-container-servlet-core

[PriyaFf]

I add that already, butstill i got same error,

…

________________________________ From: Jorge Bescos Gascon ***@***.***> Sent: Thursday, July 24, 2025 12:27 To: eclipse-ee4j/jersey ***@***.***> Cc: PriyaFf ***@***.***>; Author ***@***.***> Subject: Re: [eclipse-ee4j/jersey] SEVERE: ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer in Tomcat deployment (Discussion #5956) Did you add this dependency?: https://mvnrepository.com/artifact/org.glassfish.jersey.containers/jersey-container-servlet-core — Reply to this email directly, view it on GitHub<#5956 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BDF7JWGPVI33VSB7LMZAT2L3KB7XHAVCNFSM6AAAAACCE3ETO6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOBXGMYDCMQ>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[jbescos]

It seems your eclipse IDE is not picking it up in the classpath, or the app is not refreshed in Tomcat. The class not found is inside that jar.

I suggest you to mavenize the project, convert it as a war, and deploy it in Tomcat.

[PriyaFf]

So it is eclipse issue? But my project is non maven project. If I convert that to maven project, i use springboot?

…

________________________________ From: Jorge Bescos Gascon ***@***.***> Sent: Thursday, July 24, 2025 12:39 To: eclipse-ee4j/jersey ***@***.***> Cc: PriyaFf ***@***.***>; Author ***@***.***> Subject: Re: [eclipse-ee4j/jersey] SEVERE: ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer in Tomcat deployment (Discussion #5956) It seems your eclipse IDE is not picking it up in the classpath. The class not found is inside that jar. I suggest you to mavenize the project. — Reply to this email directly, view it on GitHub<#5956 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BDF7JWEGAJ6XAQ5L64LKL6T3KCBD5AVCNFSM6AAAAACCE3ETO6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOBXGMYTEMQ>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[jbescos]

You can use springboot with maven. Maven is a tool to help you to manage projects (building, testing, generating javadoc, etc), and it is the most used tool. This is definitely something to need to get familiar with.

If you don't know how, you can see examples or use chatgpt to help you to convert it.

[PriyaFf]

Hi.. Thak You. As per your suggestion I tried to move my project to maven. Now my issue was gone. Working fine. Once again Thank you.

…

________________________________ From: Jorge Bescos Gascon ***@***.***> Sent: Thursday, July 24, 2025 12:59 To: eclipse-ee4j/jersey ***@***.***> Cc: PriyaFf ***@***.***>; Author ***@***.***> Subject: Re: [eclipse-ee4j/jersey] SEVERE: ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer in Tomcat deployment (Discussion #5956) You can use springboot with maven. Maven is a tool to help you to manage projects (building, testing, generating javadoc, etc), and it is the most used tool. This is definitely something to need to get familiar with. If you don't know how, you can see examples or use chatgpt to help you to convert it. — Reply to this email directly, view it on GitHub<#5956 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BDF7JWAVK5SEEE2LFROSTXD3KCDMNAVCNFSM6AAAAACCE3ETO6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOBXGMZDSNY>. You are receiving this because you authored the thread.Message ID: ***@***.***>