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When developing through Netbeans in Java (my personal favourite) you may come across the annoying error now and again which is telling you that Tomcat cannot start due to the port being in use already. Often this is Port 8005 but it could be something else depending on how you have things configured. Either way, this ‘feature’ is rather annoying and requires a couple of steps to kill this off and get you back on track. Unfortunately the traditional IT solution doesn’t work in this scenario, turning Netbeans off and back on again, the issue persists.

This issue is caused when you are trying to run multiple applications simultaneously and something has got in a bit of a mess in the background.

Thankfully, the solution is rather simple when you know where to look on Windows, there are a few steps involved.

 

Find the PID (Process ID) that is hogging the Port 8005 that you need

To do this, either search for “Resource Monitor” in the Windows start menu, or, type at the command prompt, resmon.exe. Either way will open the resource monitor as you can see in the screenshot below. Look through the list of Ports and find the port that is being blocked, then look across to the PID column to find the Process ID, you’ll need this in the next step.

 

 

For those of you more familiar with the command line, just run the following command;

 

Netstat –a –o –n

 

Netstat is a command-line tool for displaying network statistics including displaying connections using the TCP/IP protocol, i.e. your application.

The –a flag displays all connections and listening ports

The –o flag displays the owning process ID associated with each connection

The –n flag displays addresses and port numbers in numerical form

Simple.

 

Next Force Kill the Process

To do this, you need to run Command Prompt as an Administrator. This will not work as a standard Windows user, you need to be an Administrator. Simply type;

 

Taskkill /F /PID 12345 (replace the process ID that you found earlier)

 

Done. You’re good to go again.

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Michael Cropper

Founder & Managing Director at Contrado Digital Ltd
Michael has been running Contrado Digital for over 10 years and has over 15 years experience working across the full range of disciplines including IT, Tech, Software Development, Digital Marketing, Analytics, SaaS, Startups, Organisational and Systems Thinking, DevOps, Project Management, Multi-Cloud, Digital and Technology Innovation and always with a business and commercial focus. He has a wealth of experience working with national and multi-national brands in a wide range of industries, across a wide range of specialisms, helping them achieve awesome results. Digital transformation, performance and collaboration are at the heart of everything Michael does.