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Web server failed to start. Port 8080 was already in use. Spring Boot microservice

I am trying to call webAPI from gradle project.
My build.gradle is as following.
plugins {
id 'org.springframework.boot' version '2.1.4.RELEASE'
id 'java'
}
apply plugin: 'io.spring.dependency-management'
dependencies {
implementation 'org.springframework.boot:spring-boot-starter'
runtimeOnly 'org.springframework.boot:spring-boot-devtools'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
compile 'org.springframework.boot:spring-boot-starter-webflux'
compile 'org.projectreactor:reactor-spring:1.0.1.RELEASE'
}
If I remove following dependency
compile 'org.springframework.boot:spring-boot-starter-webflux'
It works, but if I add it back. it gives error as
Web server failed to start. Port 8080 was already in use.
So, how do I fix this, so that I can use webclient? Because application is not web application which requires port to run. it is a sort of microservice.
I just want to use WebClient of Spring Boot. How do i use it without converting my application into web application.

If on windows and your getting this every time you run the application you need to keep doing:
> netstat -ano | findstr *<port used>*
TCP 0.0.0.0:*<port used>* 0.0.0.0:0 LISTENING *<pid>*
TCP [::]:*<port used>* [::]:0 LISTENING *<pid>*
> taskkill /F /PID *<pid>*
SUCCESS: The process with PID *<pid>* has been terminated.
If netstat above includes something like this;
TCP [zzzz:e2ce:44xx:1:axx6:dxxf:xxx:xxxx]:540yy [zzzz:e2ce:44xx:1:axx6:dxxf:xxx:xxxx]:*<port used>* TIME_WAIT 0
Then you can either wait for a little while or reconfigure to use another port.
I suppose we could write some code to randomly generate and check if a port is free when the application runs. Though this will have diminishing returns as they start to get used up. On the other hand could add a resource clean up code that does what we have above once the application stops.

You can change the default port of your application in application.properties by adding the following line:
server.port = 8090

If you don't want the embedded server to start, just set the following property in you application.properties (or .yml):
spring.main.web-application-type=none
If your classpath contains the necessary bits to start a web server, Spring Boot will automatically start it. To disable this behaviour configure the WebApplicationType in your application.properties
Source: https://docs.spring.io/spring-boot/docs/current/reference/html/howto-embedded-web-servers.html
If you application really is a Web application, then you can easily change the port using the server.port property (in your application's .properties/.yaml file, as a command line argument at startup, etc).

Another way to do this is by first checking what processes are using that specific port, then killing it using its process ID:
Run lsof -i :8080
This will identify which process is listening on port 8080.
Take note of the process ID (PID) e.g. 63262
Run kill -9 <PID> e.g. kill -9 63262

Some time if you can manually kill the that port problem can solve.
Using CurrPorts software you can view what are the running all ports in your machine and you can kill that port if you want.
You can download CurrPorts from here. (download link is in bottom of the page)
============== OR ==============
Without CurrPorts you can do this using like below method also.
CMD as run as administrator
Enter netstat -a -o -n and hit enter. Now you can see like below. Port can see Local Address column after : sign.
select the process id(not port) that your port running and type taskkill /F /PID <process_id_here> command and hit enter.

You can use npm to kill the port
**npx kill-port 8080** //8080 for example
Requirement: npm
read more: https://www.npmjs.com/package/kill-port

create /resources folder inside src/main
create application.properties file inside /resources
write server.port=9090 //(use any port number of your choice)

if port:8080 already in use error occurs:
goto command prompt
.type command> .netstat -ano
.Enter->this will show all running port check port 8080
.type command> taskkill /F /PID 8080
.process will terminate.

you can set server.port= #some-available-port number in application.properties file
or run command prompt in administrator mode and run netstat -a -o -n.
Find the process id which is using port 8080.
Run taskkill /F /PID #Processid command

It's easy we have two methods to solve.
First one is to change the port number in your application.properties i.e
server.port=9999 // something like this...
and second is, to first stop the available running server and then re-run your server again.
I am sure it work :)

If you had previously started the spring boot app and forgot to stop before hitting play again then Go to windows task manager and locate the java application(Something like "OpenJDK Platform binary" and click on End Task. (Java app not eclipse). Then try running again. It worked for me.

open command prompt as administrator
step1: netstat -ano | findstr :<enter your 4 digit port number>
netstat -ano | findstr :8080
TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 6436
TCP [::]:8080 [::]:0 LISTENING 6436
step2: taskkill /PID <enter above pid number(sometimes it shown 3/4/5/6 digits)> /F
taskkill /PID 6436 /F
SUCCESS: The process with PID 6436 has been terminated.

To reset port 8080, you need to find PID (Process ID) and specify it for the command as, for example, on the screen 10512:
taskkill /F /PID 10512

You try to use an already used port.
Ports are used on the transport layer - tcp, http is application layer and uses a transport layer to send and receive requests.
Default port exposed by spring boot app is 8080. In your case you have two solutions:
change port for your application
stop the service that uses the port you want to use

to catch java.net.BindException e with message: Address already in use and to start on other available port and to use webclient with one of 2 ports.
try {
SpringApplication.run(Application.class, args);
} catch (org.springframework.boot.web.server.PortInUseException e) {
//Runtime.exec("pkil")..
//or
SpringApplication.run(Application.class, otherargs);
//SpringApplication.run(Application.class, new String[]{"--server.port=8444"});
//when invoked recursively it is a port rebalancer for port usage among port pool with server as from client for startup stage via application restarts within many busy ports which are used before or without querying.
}

The error basically means that your port 8080 is occupied. If you are getting this error then go to your project and open application.properties and add the below line and it should work fine:
server.port = 8090

Your client application also spring boot application, whats why you have two spring boot application run in 8080 port.
Change port one of them or create a standalone java application with main class, put your web client in it and run.
As http client you can use Apache Http Client.

Today I was working in Spring Boot project and I got the same error in my project. So, what I did, I clicked on stop button beside the run last tool button and run again. Then, my project started working very well.

You can also write services.msc in your search bar in windows.Then you can find Apache Tomcat and then just stop this apache. I think its gonna be work.

It is a simple answer.If you are getting this error then go to your project then
src/main/resources and open application.properties file and mention there
server.port=8045 you can give your own number here instead of 8045
thanks

Open cmd and type "netstat -ano -p tcp."
Then, look for the port number and PID.
Open up Resource Monitor and search for the PID number
Right Click and "End Process."

Restarting my machine solved the issue although I was getting below issue:
Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Failed to start bean 'webServerStartStop'; nested exception is org.springframework.boot.web.server.PortInUseException: Port 8081 is already in use

If you getting this error again and again , then make sure server.port=(your port no) is the first line in application.properties file.

The best answer to this is to always use the "Relaunch Application" button. That will stop the web server and restart the entire app on the same port as before.
It's the button with the red square and green play icon combined.
https://i.stack.imgur.com/ICGtX.png

How to remote debug an enterprise application running on web logic server in eclipse IDE(same machine)

I am new to weblogic application server and remote debugging & have gone through several post to set up remote debugging. Some post suggest to edit setDomainEnv.cmd file while others suggest to edit startWeblogic.cmd file in my WEBLOGIC_HOME\user_projects\domains\my_domain\bin.
But neither of the solutions worked for me. Listed below are solutions which I tried :
1) Edit setDomainEnv.cmd file
set JAVA_DEBUG=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,address=%DEBUG_PORT%,server=y,suspend=n -Djava.compiler=NONE
set JAVA_OPTIONS=%JAVA_OPTIONS% %enableHotswapFlag% -ea -da:com.bea... -da:javelin... -da:weblogic... -ea:com.bea.wli... -ea:com.bea.broker... -ea:com.bea.sbconsole...
The port number is set to 8543 in the file
if "%DEBUG_PORT%"=="" (
set DEBUG_PORT=8453
)
2)Edit startWeblogic.cmd file
I added the following line at the top of the file
-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,address=8543,server=y,suspend=n
Then in eclipse,when i run debug configuration(port number : 8543), I get Failed to connect to remote VM. Connection refused.
Connection refused: connect
Please let me know
1) How remote debugging works?
2) How to set up remote debugging in eclipse with weblogic server ?
3) What is the difference between above 2 methods ?
4) Where do I need to add the debug command(-Xdebug....) in the startWeblogic.cmd file(at the top)?
5) What is the purpose of setDomainEnv.cmd file in weblogic server ?
Thanks in advance

I think it should be sufficient to just set environment variable before starting Weblogic. Start cmd and before starting weblogic set debugFlag=true. This should make weblogic open debug port which should be set to some default like 8453. You can also set DEBUG_PORT=8888 or any other free port, if you want to change it.
Start Weblogic and verify that the port has been opened. You can use tools like cports or ProcessExplorer for that (or event netstat).
In case debug port isn't open, check if you run Weblogic in development mode, because debugFlag can be ignored in production mode.
In Eclipse create a remote debug configuration (and remember that this option is not available in Run configuration that is next to it on the toolbar):
In point 3 on the screenshot select the project you deploy to weblogic that you want to debug.
It that does not work post the problems you have.

Not able to start hybris in debug mode

When tying to start Hybris in debug mode using Eclipse Kepler showing error
“Failed to connect to remote VM. Connection refused.
Connection refused: connect”
Even I tried by changing the default port also
tomcat.debugjavaoptions=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,address=8000,suspend=n
but showing the same error. Any help/suggestion will be appreciated.

Please change first debug port using below property
tomcat.debug.port=<please provide port which is free>
in local.properties file then start server using
hybrisserver.bat debug

Place tomcat.debug.port= into local.properties.
Place tomcat.debugjavaoptions=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,address=port_number>,suspend=n -Xverify:none -DforceANSI=true into local.properties
Go to eclipse Debug Configuration, set port same as in local.properties.
In commons tab check Debug option
Place tomcat.enable.debug=true into catalina.properties
Then start server hybrisserver.bat debug (For Windows OS).

tomcat.debugjavaoptions=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,address=50021,suspend=n -Xverify:none -DforceANSI=true
Close Eclipse/intelliJ
Change port
ant all & hybrisserverstart.bat debug

Step 1: Go to local.properties in config folder and add the following lines:
tomcat.debug.port=8001
tomcat.debugjavaoptions=-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,address=8001,suspend=n -Xverify:none -DforceANSI=true
Make sure the port you use (here 8001) is free.
Step 2: Go to \hybris\bin\platform\tomcat\conf\catalina.properties and add:
tomcat.enable.debug=true
Step 3: ant all
Step 4: hybrisserver.bat debug
Personally tried and tested, works fine!

which version of hybris are you using?
How do you currently start hybris? Is hybris and eclipse on the same machine? do you have admin privileges?
i am using hybris 3.1 with eclipse-helios.
First i start hybris without eclipse in debugmode: using ...\platform\tomcat-6\bin\debug.bat at commandline.
After that i start debugging by attaching the eclipse-debugger to that debugmode-running hybris instance using a eclipse debug configuration "remote java application" with connection Properties: host=localhost, port=8000.

you should run your hybris server with -debug option in console and by default connect debugger to port 9000 . that worked with me

Go to ...\hybris\bin\platform and run hybrisserver.bat debug in windows
or hybrisserver.sh in unix
This will start the hybris server in debug mode
During server start up, you can see a line that says hybris server starting in debug mode at the very start.

Running hybris\bin\platform\hybrisserver.bat debug should start your server ready to debug but all it actually does is use the configuration in hybris\bin\platform\tomcat\conf\wrapper-debug.conf. So you need to check that file and add the following lines if they are missing:
wrapper.java.additional.34=-Xdebug
wrapper.java.additional.35=-Xnoagent
wrapper.java.additional.36=-Xrunjdwp:transport=dt_socket,server=y,address=8000,suspend=n
Note the numbers (e.g. 34, 35, 36) need to be adapted according to which additional lines you already have in your .conf file.
Start hybrisserver.bat debug and wait till it's fully started. Then you can connect on port 80 (set in IntellJ under Run -> Edit Configurations -> Remote...)

Open file hybris\bin\platform\tomcat\conf\wrapper-debug.conf and go to the following line:
wrapper.java.additional.36=-Xrunjdwp:transport=dt_socket,server=y,address=8000,suspend=n
In that change port number 8000 to 8001.

Not able to debug webservice code in IntelliJ

I have a window service that I have installed.I have the source code of the application opened in Intelli J.
I made configuration IntelliJ as following
I checked the PID of the service and port it is using.
While running Remote config in Intelli J it is giving following error
4:09:18 PM Error running Remote: Unable to open debugger port : java.net.ConnectException "Connection refused: connect"
Can someone please shed some light on how to debug window service in IntelliJ. It is a job schedule application.
The installService.cmd is as follows
set HOME_DIR=%~dp0
set SERVICE="Service_Name"
SET JAVA_OPTIONS=-Xms256m -Xmx256m
#echo Service name is Service_Name
"pathname\Service_Name.exe" -install %SERVICE% %JVM% %JAVA_OPTIONS% -Djava.class.path="pathname\Service_Name.jar" -Dorg.quartz.properties="pathname/Service_NameScheduler.properties" -start com.org.st.Service_Name -stop com.org.st.Service_Name -out "D:/core_log\Service_Name_service_out.log" -err "D:/core_log\Service_Name_service_error.log" -current "pathname\apps"
set JVM="C:/Program Files/Java/jdk1.6.0_29/jre/bin/server/jvm.dll"

Check the port number. It should be same as in JAVA_OPTIONS & Intellij Idea Debugger remote configuration under port no.

Please append the command line arguments from the IntelliJ debug configuration to the SET JAVA_OPTIONS line, it will be something like
SET JAVA_OPTIONS=-Xms256m -Xmx256m -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=51211
And reinstall the service.

Make sure whatever port you're listening on isn't blocked by a firewall.

Unable to debug in Java with eclipse

I am trying to debug a simple Java application on my machine using Eclipse as an IDE. When I try to debug the application by entering the Debug Perspective, I set a breakpoint and start debug. Within a few seconds, the following pop-up window:
Launching unicodeRead has encountered a problem. Cannot connect to VM.
The message dumped on the console is as follows:
ERROR: transport error 202: connect failed: Connection refused
ERROR: JDWP Transport dt_socket failed to initialize, TRANSPORT_INIT(510)
JDWP exit error AGENT_ERROR_TRANSPORT_INIT(197): No transports initialized [../../../src/share/back/debugInit.c:708]
FATAL ERROR in native method: JDWP No transports initialized, jvmtiError=AGENT_ERROR_TRANSPORT_INIT(197)
How do I correct this? Why does this happen?

I just had the same problem.
Yesterday everything worked fine, now nothing - same error as you gave. I found out that network admins made some changes in the meantime. Some firewall stuff. Problem is that Eclipse tries to establish connection to JVM at "localhost" (and some random port). When I tried pinging localhost (or 127.0.0.1) I got following:
C:\Windows\system32>ping 127.0.0.1
Pinging 127.0.0.1 with 32 bytes of data:
PING: transmit failed. General failure.
PING: transmit failed. General failure.
PING: transmit failed. General failure.
PING: transmit failed. General failure.
and
C:\Windows\system32>ping localhost
Ping request could not find host localhost. Please check the name and try again.
It seams that in some cases DNS is expected to resolve this, and if firewall prevents localhost requests to DNS - stuff breaks. I had to alter hosts file and remove comments in following lines, so I would not rely on DNS for this anymore:
# 127.0.0.1 localhost
# ::1 localhost
Although it is written that hosts file changes take effect immediately, I think that some processes locked this and restart was necessary in my case. After that, everything worked again.

Had same problem, but the solution was to run the application with -server=y option and not with -server=n.
Before:
java -agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=localhost:5005
After:
java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=localhost:5005

Looks like the same problem as here. A reboot of the pc fixed the problem there. I haven't found any other solutions.

I was seeing an error while using the -X format:
java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=4000,suspend=n myapp
The error went away when I switched to the newer format:
java -agentlib:jdwp=transport=dt_socket,server=y,address=4000,suspend=n myapp

Its Very Simple,Just do the Following Changes in eclipse.ini file.
-vm
binary\com.sun.java.jdk.win32.x86_1.6.0.u43\jre\bin\javaw.exe

I changed
-agentlib:jdwp=transport=dt_socket,address=9009,server=n,suspend=y
to
-agentlib:jdwp=transport=dt_socket,address=9009,server=y,suspend=n
and that did the trick!

My case is I have a bunch of domains refer to 127.0.0.1 in hosts file, like this:
127.0.0.1 localhost domian1.local domain2.local domain3.local
one day I added another new domain to refer to 127.0.0.1. By mistake, I put the domain in front of "localhost", like this:
127.0.0.1 domain4.local localhost domian1.local domain2.local domainx.local
After this, I always got an alert window in eclipse while debugging:
Cannot connect to VM
com.sun.jdi.connect.TransportTimeoutException
In console:
ERROR: transport error 202: connect failed: Connection refused
ERROR: JDWP: Failed to initialize transport via localhost:50470, trying localhost via 127.0.0.1:50470
FATAL ERROR in native method: JDWP No transports initialized, jvmtiError=AGENT_ERROR_TRANSPORT_INIT(197)
ERROR: transport error 202: connect failed: Connection refused
ERROR: JDWP Transport dt_socket failed to initialize, TRANSPORT_INIT(510)
JDWP exit error AGENT_ERROR_TRANSPORT_INIT(197): No transports initialized [../../../src/share/back/debugInit.c:690]
The solution is keep "localhost" at the first position all the time.
127.0.0.1 localhost domian1.local domain2.local domainx.local domain4.local

What solved for me was deleting the entire domain1 folder inside the domains folder on glassfish main folder.
Eclipse will ask you to recreate a domain and then everything works again.

In eclipse select Run tab -> Debug configuration -> Junit -> select your test name ->
Environment tab -> add variable server=y .

I was getting the same error on my ubuntu machine because of a mishap with the /etc/hosts file. I had commented out the mapping of localhost to 127.0.0.1, and to complicate matters further there was a swap file hanging around.
This was the first line of my /etc/hosts:
127.0.0.1 #localhost
Deleting the # fixed the problem, whereas rebooting understandably had not.

My cause & solution were completely different.
I think in my case it was due to the installation of JProfiler. I fixed it by uninstalling JProfiler and launching eclipse with the -clean option. I suspect that JProfiler was inserting itself in the debugger. The -clean option forces Eclipse to re-assess its plugins, so that alone might have been sufficient.

Continuing #gonadarian's answer, it seems Eclipse uses port 127.0.0.1 for debug purposes. This port is also called localhost. The way this error can be removed is by ensuring that there are no processes or services running on the above ports. The way to do this, on Linux is:
As root, enter the command:
netstat -tulpn | grep 127.0.0.1
If there are processes running on the above port, it will show up in the format:
process_id/process name.
Kill the above processes like so: kill -KILL process_id
Restart the computer for these changes to take effect. The error should no longer occur.