Spring Tool Suite - Port 8080 required by Pivotal tc Server Developer Edition v3.0 is already in use

Question

I get the following error when running codes in Spring Tool Suite.

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Port 8080 required by Pivotal tc Server Developer Edition v3.0 is already in use. The server may already be running in another process, or a system process may be using the port. To start this server you will need to stop the other process or change the port number(s).

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Below is a screenshot of the error.

Also, below is what I get on localhost:8080

By changing port numbers in server.xml (i.e. <Connector acceptCount="100" connectionTimeout="20000" executor="tomcatThreadPool" maxKeepAliveRequests="15" port="${bio.https.port}" protocol="org.apache.coyote.http11.Http11Protocol" redirectPort="${bio.https.port}"/> ), I get the same error with different port numbers.