Big Sur: too many open files

Open Terminal and issue the following command(s):

ulimit -a

What is the "Maximum number of open file descriptors"? (256 is the default)

Try

ulimit -n 10240 (others have determined this to be some sort of maximum with macOS)

Then test maven from this same command prompt as the value will reset to the default if you close out this shell session.

If this works, you can set the ulimit in your .zshrc / .bashrc etc.

Another possibility to set the soft and hard limits is to create a LaunchDaemon. Apparently, this is the way to do it since High Sierra.

Create a file at /Library/LaunchDaemons/limit.maxfiles.plist

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"  
        "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">  
  <dict>
    <key>Label</key>
    <string>limit.maxfiles</string>
    <key>ProgramArguments</key>
    <array>
      <string>launchctl</string>
      <string>limit</string>
      <string>maxfiles</string>
      <string>64000</string>
      <string>524288</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>ServiceIPC</key>
    <false/>
  </dict>
</plist> 

Make sure the file is owned by root:wheel

Then

sudo launchctl load -w /Library/LaunchDaemons/limit.maxfiles.plist

Test

launchctl limit maxfiles

How many files and processes are you actually opening with your maven jobs?

lsof -p <pid of jvm> > lsof.log

Here's another launchDaemon for max processes

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple/DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
  <plist version="1.0">
    <dict>
      <key>Label</key>
        <string>limit.maxproc</string>
      <key>ProgramArguments</key>
        <array>
          <string>launchctl</string>
          <string>limit</string>
          <string>maxproc</string>
          <string>2048</string>
          <string>2048</string>
        </array>
      <key>RunAtLoad</key>
        <true />
      <key>ServiceIPC</key>
        <false />
    </dict>
  </plist>

FYI,

I see several bug fixes on Apache Issues for Maven in regards to this issue. Are you running an updated Maven version?

Perhaps you are generating a ridiculously large number of open files / processes.

Is one running Parallels Desktop 16.5 for Mac Supports Both M1 and Intel Chips

To clarify, the kernel has its limits but so does the shell. This is to adjust the shell limit.