Catch exceptions within an entire Java application [duplicate] - java

This question already has answers here:
Java: Global Exception Handler
(6 answers)
Closed 8 years ago.
Is there any method to handle/catch all exceptions thrown by a Java application, without spamming costly try{}catch(Exception e){} statements everywhere?
For example, PHP has the function set_error_handler().
Back story - Despite tough testing, sometimes bugs can get through, and users are always less than cooperative with helping to fix these.
Ideally, I'd like to hook the application up to a web service facility that can keep track of any stack traces thrown by a user's application.

Perhaps you're looking for Thread.setDefaultUncaughtExceptionHandler() ?

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How spring manages threads for multiple api requests [duplicate]

This question already has answers here:
How to increase number of threads in tomcat thread pool?
(3 answers)
Closed 6 years ago.
I am working on spring project. I put Thread.sleep(60000) on one api to check thread safety. If I call that api then all other apis wait for that time. I thought every api request processed by separate threads. So what is the reason behind this behaviour?
Issue resolved when I set maxThreads in tomcat server.xml file.
Thank you all for helping me resolve this issue.

How Java is Architectural neutral? [duplicate]

This question already has answers here:
What is the difference between "architecture-neutral" and "portable"?
(9 answers)
Closed 6 years ago.
I read that "Java is architectural neutral because it have the capacity to read the factor key of one processor into the factor of another processor."
Please explain me in detail the above statement?
Java was designed to support applications on networks.
To enable a Java application to execute anywhere on the network, the compiler generates an architecture-neutral object file format--the compiled code is executable on many processors, given the presence of the Java runtime system

Cronjob with JavaServlets on TomCat Server [duplicate]

This question already has answers here:
How to run a background task in a servlet based web application?
(5 answers)
Closed 6 years ago.
I have a webpage written with jsp and Java Servlets on a TomCat-Server.
I am very new to the whole JavaServlet thing. In the past I developed often in php. There it is very simple to create a Cronjob.
I just used CRONTAB and called a .php-file which did the job for me.
But how do I do this with JavaServlets? I read that some say the quartz-library would be good. But I didn't really get how to use this. I don't know where to start.
I know that this question isn't very detailed and I can't provide any code, because there is no. I just wonder if there is any possibility to just call a JavaServlet like I can in php with crontab.
My goal is to call a method every five minutes on my server. Most times this method will finish very quickly, but sometimes it will execute another .jar and last many minutes.
Any advice would be very helpful for me. Thanks!
I recommend that you do take a look at Quartz when you have time.
We have found it to be quite useful for handling cron-like task running.

Gracefully shutting down a program using the presence of a file - Good or bad? [duplicate]

This question already has answers here:
Best Way to Gracefully Shutdown a Java Command Line Program
(7 answers)
Closed 8 years ago.
Assume I have a daemon-style Java program (one that repeatedly executes a code block forever until terminated). I have code in it to periodically check for the presence of a file, and if present, delete the file and gracefully shut the program down.
To shut down the program, rather than killing its process, I would simply touch the file and wait for the program to shut down (and for the file to disappear).
Is this a good practice or bad practice? What are the reasons?
What other ways can the graceful shut down of a Java program be implemented?
Note: I already saw this question, however none of the answers satisfy the questions above.
What if the process crashes? Now the file exists and the program will never start up again?
I've seen this mechanism used before, and that's always a weak point.

How to test if a file is open in Java? [duplicate]

This question already has answers here:
Check if file is already open
(8 answers)
Closed 4 years ago.
Is it somehow possible to test if a java.io.File is currently open in another process by any process ? I am using Java 7 and target platforms are Linux/Windows/Mac.
There is no easy way in Java to go about this that will work reliably across different platforms. Depending on what you're trying to do, you might be able to patch together a series of try/catch statements which ostensibly work for most cases on most file systems, but you can never have full certainty that the next situation it encounters won't throw it off.
If you do end up going this route you want to ensure that when there is any doubt, it fails fast and doesn't get into a situation where it thinks a file is not open when it really is. My advice would be to see if there is any way you can possibly work around having to do this check.

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