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Why Elastic Beanstalk stop working?

I am completely new to the AWS and I have successfully deployed my Java program to Elastic Beanstalk.
First 30 minutes or sometimes even 6 hours it's working pretty fine.
But later I always got a message:
"Environment health has transitioned from Ok to Warning. 1 out of 1 instances are impacted. See instance health for details."
or
"Environment health has transitioned from Ok to Warning. 100.0 % of the requests are failing with HTTP 5xx."
And my site stop working and when I try to access it through my browser it's says
"Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /.
Reason: Error reading from remote server"
If I run my program on my computer its work fine without errors. So I think the problem is in my AWS Environment.
I am using free t2.micro instance - does it have some limits for processing power in hour or something like that?
If it's not - how can I find whats wrong is going on with my Environment or Instance ?

http 5xx error is coming from your application server and is most probably not AWS issue.. Please check server logs of your server.
Yes every server ( micro or the biggest server in this world ) has some limits; but I don't think thats the problem in your case..

Per the documentation, t2.micro instances only have 1GB of RAM. I suspect that your application is consuming more than that after some amount of time. As #Deepak suggested, your application logs should illuminate the problem.
All t2 instances are Burstable Performance Instances, which means that after a sustained period of load, their performance will drop off significantly. However, that alone shouldn't be causing your 5xx errors.

Tomcat restarts with errors (exit 143), runs and then fails after time

This is my first time asking a question on Stack Overflow. I recently configured an Ubuntu 16.04 virtual private server to host a web application. I run ngnix on a Tomcat server that reads and writes to a MySQL database. The application runs fine except for the fact that Tomcat restarts itself once in a while which results in a 500 error that stems from a "broken-pipe" when anyone tries to login (i.e. make a connection to the database).
I will post an image of the 500 next time it happens. I went into my vps and looked at my Tomcat restart message. This is what I see: Tomcat status message.
I also did a little diving into the Tomcat logs and this is a log file that corresponds with that restart time: Tomcat log file
I did some research to try and solve this myself, but with no success. I believe that the exit=143 is the process being terminated by another program or the system itself. I also have done some moving of the mysql-connector-java.jar. I read that it should be located in the Tomcat/lib directory and not in the WEB-INF of the web application. Perhaps I need to configure other settings.
Any help or any direction would be much appreciated. I've fought this issue for a week with having learned much, but accomplished little.
Thanks

Look at the timeline. It starts at 19:49:23.766 in the Tomcat log with this message:
A valid shutdown command was received via the shutdown port. Stopping the Server instance.
Exit code 143 is a result of that shutdown and doesn't indicate anything.
The question you need answered is: Who send that shutdown command, and why?
On a side note: The earlier messages indicates that Tomcat lost connection to the database, and that you didn't configure a validation query. You should always configure that, since database connections in the connection pool will go stale, and that needs to be detected.
Theory: Do you have some monitoring service running that tests your application being up? Does that monitoring detect a timed-out database connection, classify that as a hung webapp and auto-restart Tomcat?

While I don't think I am able to see to the core of the problem you have with your overall setup given the small excerpt of your log files, one thing strikes the eye. In the Tomcat log, there is the line
A valid shutdown command was received via the shutdown port. Stopping the server instance.
This explains why the server was restarted. Someone (some external process, a malicious attacker, script, or whatever. Could be anything depending on the setup of your server) sent a shutdown command to Tomcat's shutdown port (8005 by default) which made the Tomcat shut down.
Refer to OWASP's recommendations for securing a Tomcat server instance for fixing this possible security whole.
Regarding the ostensible Hibernate problems you have, I don't get enough information from your logs to make a useful statement. But you can leave the MySQL jar in Tomcat/lib, since this is not the root cause of your problem.

Android application access my server but got a timeout error

My app client access my Tomcat. Some times it works well, but sometimes it times out - especially when two people quickly flush the frame to access the server. What might be the problem?
I can make sure that my database doesn't hang. Because I also have a management system on my Tomcat and they use the same database. The system works well even if my app can't access the server.

First check your server tomcat running system configuration, like ram capacity and internet speed ect.. because it seems to be you are using same system for data base also.
Some time bad/ slow network connections in client side also will cause
this kind of time out errors, So just add conn.setTimeout(60000) line in from your client code near http call.

windows service access to network before logon

I wrote a windows service in Java, and it starts automatically (before user login to Windows).
My problem is that it looks like the service has no access to the network before logon.
In the logs I see that before logon, I get: java.net.UnknownHostException. However, the same code works fine after logon.
I tried to define the service as "network service", it did not helped.
Can anyone please help?
BTW:
There is no WiFi involved
I looked how TeamViewer program works and I saw that they have some registry values in FirewallPolicy. and they defined their service as local system.
Which made me think maybe it has something to do with the firewall settings, however I cannot find anything in the web about it.

I just managed to solve this. The issue was that the service started before there was access to the internet. Keep in mind that the network might be accessible but the internet isn't.
I solved it by doing: (pseudo code)
while (false) {
check if http://www.example.com is accesible:
if true - break
if false - sleep for 3 seconds
}
... (rest of the code)

If the exception one gets is UnknownHostException, this would imply that somehow DNS resolution failed..
Note further that DNS resolution itself depends on IP. Hence, if the machine in question is slow to connect to the respective gateway (router), then DNS resolution has no chance of succeeding.
Hence, while you may try to resolve the host resolution in a loop with a sleep (as suggested by Kuf).. I'd suggest try to log how soon does the machine gets the IP address after the reboot (a sign of how soon it gets connected to the Network), and then go from there (additional SuperUser or ServerFault question perhaps).

Tomcat shuts down automatically

I'm using Apache and Tomcat on a Windows server and since this morning, Tomcat stops working without any logs. It doesn't hang, it just shut down.
There's no log in Tomcat, the CPU/Memory are fines, there are no System.Exit in my code.
Anybody ever had this problem?
It happens at random, after 5-10 minutes. The application responds normally and sometime, boom.. stops working.
UPDATE : Still no clue. The Admin team will install the webapp on another box...

My script to start tomcat had last line tail -f catalina.out.
Sometime I did not kill this script, the shell then timed out and killed the script with all child processes, including tomcat.

This sounds like the JVM is crashing. Have you looked for a JVM crash log? It typically has a name like hs_err_pid*.log and is created in the JVM's working directory.
If you find a file like this and upload it, then we can probably help more.
Some questions:
Have you recently changed the version of Java you are using?
What is the exact version of Tomcat you are using?
Are you using Tomcat Native (the Apache Portable Runtime)?

Faced this issue recently.
Scenario : Tomcat started successfully but automatically gets shut down after 1 hour and sometimes this happened after 1 day and nothing is there in tomcat logs.
Issue : Actual issue was high memory usage and no free SWAP memory.
How I found the solution
If tomcat don't show any logs, then there must be something in system logs so, I checked /var/log/messages but since permission denied for me I tried /var/log/dmesg and got this
"Out of memory: Kill process 14606 (java) score 106 or sacrifice child".
In the output I noticed Swap Memory free 0 K. Ran top command to confirm the same. So, somehow there was a high memory usage which caused the OS to kill my tomcat process.
After spending hours finally got the reason.
ps -ef | grep tomcat showed that there were several tomcat processes running for the same application. It seems that, earlier tomcat shutdowns might not have taken successfully and the processes were not killed even after the shutdown due to some reason, which was causing the high memory usage.
So, killed all running tomcat processes using kill. SWAP memory got freed.
Started tomcat again, worked fine. :)

Recently I had this problem, If somebody faces the same issue in future I hope this will help.
Scenario: Tomcat shuts down without any logs or errors
Root Cause for my problem: synchronized method accessed from a task using TimerTask
I had a singleton class with a synchronized method accessed from various threads based on timer or user action
some times this method will take up to few minutes to complete. When TimerTask is waiting on this method for sometime (I guess timer is timed out /thread is killed or something is happening in the background) and the moment the lock on the method is released the tomcat is getting killed.
So I removed synchronized keyword and removed singleton and made some code changes for thread safety. Then the problem is gone.
How I found out: I had a log statement in the first line of synchronized method and everytime the tomcat shutdowns i found this message in the last few lines.
Regards,
Phanindra Kasturi

things to look for in debugging an issue like this:
Look at the logs directory ($TOMCAT_ROOT/logs) to make sure none of the log files have any stack traces
Look at the tomcat startup script to make check the location of the log files to see if the logs are not being written to another directory.
Another reason could be some other user/process could be issuing a kill -9 that could kill tomcat without giving it any chance to log errors.

another possibility is that some process was started this morning on the box that is binding to a port that your server requires.

Are your servlets or one of it's dependencies allowed to call System.exit()? (Not sure how locked down Tomcat VMs are in that sense)
I've had developers thinking it's ok to use exit(666); on detecting a non-invertable matrix (which isn't good, but sure as heck not fatal). Arrgh. Perhaps you have some similar culprit in your system?

I noticed CATALINA_OPTS in my path and that was set for a lower JVM size. Hence, the crash and no log trace of tomcat was found. The server automatically shutdown in less than 2 hrs.
check, CATALINA_OPTS or JAVA_OPTS -- these might have jvm settings. either increase them or comment them out and increase the swap memory.

“The Service on local computer started and then stopped ,Some services stop automatically if there are not in use by other services or programs.”
I gone through the problem i have tried so many ways to get out of the problem finally i got the solution as follows.
1) Click Run Command from start button.
2) Enter Services.msc then click OK,you will get all the services in your computer.
3) Select your service and right click on the service and select Properties
4) Goto Logon Properties and select Local System Account then click OK.
This will work.

Sometime it happens if some other program is running on the same port. For example Skype. Shut down that program before you start Tomcat.

try to clean your elipse projects because you could have tried to add another server which used port 8080 then when you try to execute the tomcat server externally that defaulty uses port 8080 the tomcat server automatically shutdowns after cleaning the project copy the new war file and paste it in bin it works fine
conclusion: when the server tries to use the port which has already been acquired you will see such type of issues.