When launching a Spring Boot application, you might encounter the error “Address already in use”. This typically occurs when the default port (8080) is already occupied. Here are some solutions to resolve this issue:
Solution 1: Change the Application Port
Spring Boot applications use embedded Tomcat servers by default. You can easily change the port as follows:
Option 1: Use Command Line
Run the following command to specify a different port:
java -jar target/gs-serving-web-content-0.1.0.jar --server.port=8181
Option 2: Update Configuration
Modify your application.properties
or application.yml
file to set a new port:
server.port=8181
Solution 2: Kill the Process Using the Port
Identify and stop the process occupying the port (e.g., 8080).
On Linux/MacOS:
- Find the process:
lsof -i :8080 | grep LISTEN
Example output:
java 78960 xyxss 119u IPv6 0x6c20d372bc88c27d 0t0 TCP *:8080 (LISTEN)
- Kill the process:
kill -9 78960
On Windows:
- Find the process:
netstat -ano -p tcp | find "8080"
Example output:
TCP 0.0.0.0:8080 LISTENING 1234
- Kill the process:
taskkill /F /PID 1234
Solution 3: Verify Port Usage
Option 1: Use Telnet
Run:
telnet localhost 8080
or visit:
http://localhost:8080
If the port is in use, change the port in your application.properties
file:
server.port=8181
Option 2: Check with Netstat
On Linux/MacOS:
netstat -pnltu | grep -i "8080"
On Windows:
netstat -ano -p tcp | find "8080"
Solution 4: Modify IDE Configuration
If you are running your application via an IDE like IntelliJ IDEA, you can modify the port in the Run Configuration:
- Go to Run → Edit Configurations.
- Add
--server.port=8181
to the program arguments.
Solution 5: Use Maven
Run the application with a custom port using Maven:
mvn spring-boot:run -Dserver.port=8181
Extra Tips
Sometimes, you may need to change other related ports:
management.port=8182
tomcat.ajp.port=8009
Additionally, ensure no other services like Docker or another Tomcat instance are using the port.
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