对导致服务器因“打开的文件过多”而挂起的 Java 程序进行故障排除

Question

I have a Java program runs (on linux) for a while and then causes the server to lock up with "Too many files open"

After restarting the machine, I run the java program again and then execute the lsof command against it's pid. A large number of lines with the following output are produced:

java    971 uknown  980u     sock                0,9       0t0  20461 protocol: TCPv6

Does this means the program is opening multiple tcp connections & not closing them?

What further steps can i take to troubleshoot this?

Answer 1

It means your program is opening file descriptors but not closing them. It may be sockets or file handlers. So it is causing resource leak. Make sure all file handlers are closed and make it ready for garbage collected.

As dan1st pointed out in comment, one preventive measure to avoid this scenario is using try-with-resources. This will implements the AutoClosable interface and make sure automatic resource closing.