Servlet returns "HTTP Status 404 The requested resource (/servlet) is not available"

Scenario #1: You accidentially re-deployed from the command line while tomcat was already running.

Short Answer: Stop Tomcat, delete target folder, mvn package, then re-deploy

Scenario #2: request.getRequestDispatcher("MIS_SPELLED_FILE_NAME.jsp")

Short Answer: Check file name spelling, make sure case is correct.

Scenario #3: Class Not Found Exceptions (Answer put here because: Question# 17982240 ) (java.lang.ClassNotFoundException for servlet in tomcat with eclipse ) (was marked as duplicate and directed me here )

Short Answer #3.1: web.xml has wrong package path in servlet-class tag.

Short Answer #3.2: java file has wrong import statement.

Below is further details for Scenario #1:

1: Stop Tomcat

• Option 1: Via CTRL+C in terminal.
• Option 2: (terminal closed while tomcat still running)
• ------------ 2.1: press:Windows+R --> type:"services.msc"
• ------------ 2.2: Find "Apache Tomcat #.# Tomcat#" in Name column of list.
• ------------ 2.3: Right Click --> "stop"

2: Delete the "target" folder. (mvn clean will not help you here)

3: mvn package

4: YOUR_DEPLOYMENT_COMMAND_HERE

(Mine: java -jar target/dependency/webapp-runner.jar --port 5190 target/*.war )

Full Back Story:

Accidentially opened a new git-bash window and tried to deploy a .war file for my heroku project via:

java -jar target/dependency/webapp-runner.jar --port 5190 target/*.war

After a failure to deploy, I realized I had two git-bash windows open, and had not used CTLR+C to stop the previous deployment.

I was met with:

HTTP Status 404 – Not Found Type Status Report

Message /if-student-test.jsp

Description The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.

Apache Tomcat/8.5.31

Below is further details for Scenario #3:

SCENARIO 3.1: The servlet-class package path is wrong in your web.xml file.

It should MATCH the package statement at top of your java servlet class.

File: my_stuff/MyClass.java:

   package my_stuff;

File: PRJ_ROOT/src/main/webapp/WEB-INF/web.xml

   <servlet-class>
   my_stuff.MyClass
   </servlet-class>

SCENARIO 3.2:

You put the wrong "package" statement at top of your myClass.java file.

For example:

File is in: "/my_stuff" folder

You mistakenly write:

package com.my_stuff

This is tricky because:

1: The maven build (mvn package) will not report any errors here.

2: servlet-class line in web.xml can have CORRECT package path. E.g:

<servlet-class>
my_stuff.MyClass
</servlet-class>

Stack Used: Notepad++ + GitBash + Maven + Heroku Web App Runner + Tomcat9 + Windows10:

Check if you have entered the correct URL Mapping as specified in the Web.xml

For example:

In the web.xml, your servlet declaration maybe:

<servlet>
        <servlet-name>ControllerA</servlet-name>
        <servlet-class>PackageName.ControllerA</servlet-class>
</servlet>

<servlet-mapping>
        <servlet-name>ControllerA</servlet-name>
        <url-pattern>/theController</url-pattern>
</servlet-mapping>

What this snippet does is <url-pattern>/theController</url-pattern>will set the name that will be used to call the servlet from the front end (eg: form) through the URL. Therefore when you reference the servlet in the front end, in order to ensure that the request goes to the servlet "ControllerA", it should refer the specified URL Pattern "theController" from the form.

eg:

<form action="theController" method="POST">
</form>

If you're using IntelliJ, this is what fixed it for me:

Go to the Tomcat configuration:

Configuration > Deployment Tab

Scroll down and add / to the Application Context dropdown

Solution for HTTP Status 404 in NetBeans IDE: Right click on your project and go to your project properties, then click on run, then input your project relative URL like index.jsp.

1. Project->Properties
2. Click on Run
3. Relative URL:/index.jsp (Select your project root URL)

My issue was that my method was missing the @RequestBody annotation. After adding the annotation I no longer received the 404 exception.

Do the following two steps. I hope, it will solve the "404 not found" issue in tomcat server during the development of java servlet application.

Step 1: Right click on the server(in the server explorer tab)->Properties->Switch Location from workspace metadata to tomcat server

Step 2: Double Click on the server(in the server explorer tab)->Select Use tomcat installation option inside server location menu

I removed the old web library such that are spring framework libraries. And build a new path of the libraries. Then it works.

An old thread, but since I didn't find it elsewhere, here is one more possibility:

If you're using servlet-api 3.0+, then your web.xml must NOT include metadata-complete="true" attribute

This tells tomcat to map the servlets using data given in web.xml instead of using the @WebServlet annotation.

First of all, run your IDE as Admin. After that, right click the project folder -> Project Facets and make sure that the Java Version is set correct. On my PC. (For Example 1.8) Now it should work.

Don't just start your server, for example Wildfly, using the cmd. It has to be launched within the IDE and now visit your localhost URL. Example: http://localhost:8080/HelloWorldServlet/HelloWorld

The fix that worked for me is(if you are using Maven): Rightclick your project, Maven -> Update project. This might give you some other error with the JDK and other Libraries(in my case, MySQL connector), but once you fix them, your original problem should be fixed!

If you would like to open a servlet with javascript without using 'form' and 'submit' button, here is the following code:

var button = document.getElementById("<<button-id>>");
button.addEventListener("click", function() {
  window.location.href= "<<full-servlet-path>>" (eg. http://localhost:8086/xyz/servlet)
});

Key:

1) button-id : The 'id' tag you give to your button in your html/jsp file.

2) full-servlet-path: The path that shows in the browser when you run the servlet alone

Mapping in web.xml is what i have done :-

1. If there's another package made for new program then we must mention :-

packagename.filename between opening and closing of servlet-class tag in xml file.

2. If you are mapping your files in xml and they are not working or showing errors , then comment on the annotation line of code in the respective files.

Both methods dont work with one another , so either i use annotation method of files mentioned when we create servlet or the way of mapping , then i delete or comment the annotation line. Eg:

 <servlet>
   <servlet-name>s1</servlet-name>
   <servlet-class>performance.FirstServ</servlet-class>
   </servlet>    
   
   <servlet-mapping>
   <servlet-name>s1</servlet-name>
   <url-pattern>/FirstServ</url-pattern>
   </servlet-mapping>
   
   <servlet>
   <servlet-name>s2</servlet-name>
   <servlet-class>performance.SecondServ</servlet-class>
   </servlet>
   
   <servlet-mapping>
   <servlet-name>s2</servlet-name>
   <url-pattern>/SecondServ</url-pattern>
   </servlet-mapping>

Commenting the annotation line of code in the respective file,if mapping in xml is done.

//@WebServlet("/FirstServ")
//@WebServlet("/SecondServ")

If someone is here who is using MySQL and felt that the code was working the previous day and now it doesn't, then I guess you must open MySQL CLI or MySQL Workbench and just make the connection to the database once. Once it gets connected, then the database also gets connected to the Java Application. I used to get the Hibernate Dialect error stating something wrong with com.mysql.jdbc.Driver. I think MySQL in some computers has a startup problem. This solved for me.

If you are a student and new to Java there might be some issue going on with your web.xml file.

1. Try removing the web.xml file.
2. Secondly check that your path variables are properly set or not.
3. Restart tomcat server Or your PC.

Your problem will be surely solved.

I was facing this issue too, I was receiving a 404 when accessing a URL pattern that I knew was linked to a Servlet. The reason is because I had 2 Servlets with their @WebServlet name parameter set as the same string.

@WebServlet(name = "ServletName", urlPatterns = {"/path"})
public class ServletName extends HttpServlet {}

@WebServlet(name = "ServletName", urlPatterns = {"/other-path"})
public class OtherServletName extends HttpServlet {}

Both of the name parameters are the same. If you're using the name parameter, make sure they are unique compared to all other Servlets on your application.

I had the same issue. Tried all of this but didn't help. I managed to solve this issue by adding element tags to beginning and end of the xml file. ill leave my xml file below for reference.

<?xml version="1.0" encoding="UTF-8"?>

<element>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
     
<servlet> 
    <servlet-name>InsertServlet</servlet-name> 
    <servlet-class>com.worklog.InsertServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
    <servlet-name>InsertServlet</servlet-name> 
    <url-pattern>/insert</url-pattern> 
</servlet-mapping>

</web-app>

</element>

I was having the same issue. I was developing a mvc based REST API where there was no explicit html configuration or files. The API was using Swagger to generate a user interface. The problem started when I introduced Swagger version "3.0.0". I reverted back to Swagger "2.9.2" This solved my problem.

<!-- Swagger -->
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>2.9.2</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>2.9.2</version>
    </dependency>

Please check context root cannot be empty.

If you're using eclipse:
right click, select properties, then web project settings. Check the context root cannot be empty