When developing a Spring project using the Spring Tool Suite (STS) IDE, you may encounter an error message indicating that the 8080 port is already in use. This can happen if there is another application or process running on your system that is using the same port. In this blog post, we will discuss the cause of this issue and provide step-by-step instructions for resolving it.
Understanding the 8080 Port Conflict
The 8080 port is a well-known port commonly used by application servers, including the Apache Tomcat server used by STS. When you try to deploy your Spring project from STS, the IDE attempts to start a Tomcat server on the 8080 port. If this port is already in use by another application or process, you will receive an error message indicating that the port is already taken.
Identifying the Process or Application Using the 8080 Port
To resolve the 8080 port conflict, you need to identify the process or application that is using the port. You can do this by using the netstat
command in a terminal or command prompt.
netstat -ano | find "8080"
The output of the netstat
command will display a list of all active connections on your system. Look for a line that contains :8080
and note the process ID (PID) in the right-most column.
Stopping the Process or Application Using the 8080 Port
Once you have identified the process or application using the 8080 port, you can stop it in one of two ways:
- Terminate the process using the Task Manager (Windows) or the Activity Monitor (macOS).
- Stop the application or service that is using the port.
Changing the Port for the Tomcat Server in STS
If you are unable to stop the process or application using the 8080 port, or if you prefer not to, you can change the port used by the Tomcat server in STS. To do this, follow these steps:
- Right-click on your Spring project in the STS Project Explorer and select
Properties
. - In the
Properties
window, selectServer
and thenTomcat v9.0 Server
. - In the
Tomcat v9.0 Server
section, change theHTTP/1.1
port to a different number, such as8081
. - Save your changes and try to redeploy your project. The Tomcat server should now start on the new port.
Conclusion
The 8080 port conflict is a common issue when deploying a Spring project from STS. By identifying the process or application using the port, stopping it, or changing the port used by the Tomcat server, you can resolve this issue and successfully redeploy your project.