What are the possible causes for when the Linux top command shows a Java process is using 14GBs of memory while Java profiling shows only 2GBs being used? Answer That means that your JVM / Java application is using off-heap memory. Lots of it. It could be memory-mapped files. It could be native libraries: unl…
Tag: java
How tomcat handle multiple concurrent request at the same time?
How tomcat handle multiple concurrent request at the same time ? Does it queues up the requests or processes some of the requests in parallel ? If it processes requests in parallel , how does it returns the asynchronous response ? Does it keeps the connection open with client until response comes ? If the tom…
OSGi declarative service is active, but bind() is not called
I’m facing an issue in OSGi context with declarative services which I don’t understand. I try to explain: I have a FooService which needs the FooManagerService (1..1 static). The FooManagerService references the FooService, but it’s optional (0..n dynamic). The goal is, if a FooService becom…
How to run node server and java server in same command line in package.json start
I need to run : And : I tried : Or But in both case the java server is not running when I ask it in the node applicaition. But if I run both commande in 2 differents console. There is no problem. Thank you Edit: I try to do it in the npm start Answer Ok so I found
Need to run .jar from console for it to work
I have a java application. I’m using eclipse to write, compile and create a runnable .jar. The program is used to discover OCF devices. It uses UDP and multicast. Multicast code The code works when I start it from eclipse. It also works when I run the .jar from console on Linux. But when I start it with…
Linux time conversion fail
My program will take the current system time in HH:MM:SS and convert it into seconds. The reason i convert it into second is because i want to find out the time that was 90 seconds ago. For example :Current time : 12:30:30Time 90 sec ago : 12:29:00 But i can’t make it to the correct timestamp. Here are …
`spring.config.location` is ignored
Fairly straight forward. I have a configuration file: I run my application as a follows: And logging indicates the setting is visible to the application: 04:28:16.919 [main] WARNING CONFIG- [–spring.config.location=file:///etc/my-application] But my settings are ignored: The following yields the same ou…
dot dot(..) pathing doesnt work on java new file with linux running jenkins
I have this in a maven build on Jenkins. It’s being used to generate files. It works when building on my local machine(windows 7) but doesn’t work when i run it on Linux. It looks like it’s taking the .. as a literal folder path and not going back a directory. The error is: Answer Using base…
Linux top output unrealistic?
I’m having a weird issue with a java process which is consuming a lot of resources on a linux VM. The output of top for the process is the below : So this shows that the process is actually consuming 21G of physical memory ? When checking the process in more detail I can see it was started with -Xmx4G
java.lang.NullPointerException and return code
I’m running some java binary from bash like: run_me.sh but inside application I get java.lang.NullPointerException, howewer return code is 0, but I need some non zero exit code to understand from bash that application failed. What is the proper way to handle such cases? Update: Here is an exxample of &#…