Resolving OutOfMemoryError: unable to create new native thread

(This was tested on Red Hat EL6 JDK 1.6.31 64-bit)

If you've ever come across this error, it can be very misleading.
Caused by: java.lang.OutOfMemoryError: unable to create new native thread
 at java.lang.Thread.start0(Native Method)
 at java.lang.Thread.start(

The common suggestion (as the error suggests) is a memory related problem. Some tips but ultimately unhelpful:
The common theme amongst all of them is the stack size.

Came across this post with same test code:
However the tests were inconsistent, modified it to only go 50 calls deep. Modified code here.
We discovered that changing the options made very little difference to the maximum number of threads.

Originally we thought it was related to changing the linux option for hard/soft maximum number of files that we did the day before:
# vi /etc/security/limits.conf 
testuser soft nofile 4096
testuser hard nofile 10240
# ulimit -Hn

However that didn't seem to be it.

Then we finally came across max process per user:
ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 515005
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 4096
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 1024
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

Which is set to 1024 by default. So adding this to ~/.profile fixed it for us:
ulimit -u 4096

Update 2013/08/15:
To see the number of process for a user run this (replacing [user] with the username):
ps -eLF -u[user] | wc -l


  1. Saved my day! Ran into exactly same problem and spent hours on searching, tuning Java memory related options without success.

    This post hit the root cause for our application OOME!

    Alternatively, you can put per user limit here:

    cd /etc/security/limit.d

    Create a file similar to 90_nprof.conf with a smaller number prefix, e.g. 80_nprof.conf, then put per user process limit there.


  2. Excelent !!!

    we had the same problem with JADE Framework,

    thanks for you help, this is the solution

  3. Hi Chris and very good post on this common problem.

    You also may be interested in other common root causes of this problem such as native heap depletion of the Java process; especially for a 32-bit JVM. Thread dump analysis is also very useful when your application / Java EE container is firing too many threads.

    Looking forward for more articles from you.


  4. Thanks - a very big help! I was also trying to understand threads in Java, and found this page to be very helpful:

    How to Create a thread in Java

  5. I could not understand where this ~./profile file resides and what to be modified in that file. Please help me

  6. I agree with Hagasharath, "I could not understand where this ~./profile file resides and what to be modified in that file. Please help me". Could you clarify the step taken to perform this process?


  7. It's the environment init scripts for the current user.

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  9. Helped me too...Really good post.

  10. It helped me with "unable to create new native thread".


  11. Hi Chris,

    First, sorry for posting question in Red Hat box but I don't have solution to solve my problem :(
    How to solve the same problem on window with Java 32 bit. I faced that error.
    I try to increase -Xmx and decrease -Xss parameter but not better :(.
    I set -Xmx1024M but it increase over that value, java application stop working when reaching to maximum memory (about 1.8 GB).


    Thai Huynh

    1. Hi Thai Huynh,
      On a 32 bit machine you have to decrease the heap size to make available more memory for native processes. You can google it for more details. It is relatively simpler to fix this problem on 32 bit machine.

  12. Thank you Christopher! Your post led me in the right direction. I found a file in /etc/security/limits.d that was limiting the number of processes for all non-root users to 1024, which is not enough for Jenkins. By the way that is the "correct" place to set the limits in Linux (at least in RHEL/CentOS).

    In addition to that, you have "ps -eLF -u[user] | wc -l" which should actually just be "ps -LFu [user] | wc -l" ... the "-e" shows all processes (everyone) and overrides the -u :)


  13. Hi Chris,

    I have been facing the same issue of OutofMemory:unsable to create new native thread.
    The issue comes up when my SOAP request tries to insert\update records in database. Update fails after inserting 600 or aprox records at a time throwing the native thread error and shuts down the server.

    Although the suggestions and guideline you provided is for Linux, but since my application setup EAServer6(sybase product) is configured to run on JDK 1.7 so found the post helpful for my purpose as well.

    EAServer6(32 Bit server application) is running on Window Server 2008 R2 Standard 64bit machine.

    To run this server, script picks the below parameters:

    REM set DJC_ARCH_64=true
    REM set DJC_JAVA_HOME_17=C:\Program Files (x86)\Sybase\EAServer6\jdk\jdk1.7.0_09

    set DJC_RT_DEFAULT=17
    set DJC_JDK_DEFAULT=17

    set DJC_JVM_MINHEAP=128M
    set DJC_JVM_MAXHEAP=512M


    set DJC_JVM_USER_ARGS=%DJC_JVM_USER_ARGS% -XX:StackShadowPages=15

    REM set CLASSPATH=C:\Program Files (x86)\Sybase\Shared\PowerBuilder\pbjdbc12125.jar;C:\Program Files (x86)\Sybase\Shared\PowerBuilder\pbejbclient125.jar;%CLASSPATH%

    set CLASSPATH=%CLASSPATH%;C:\Program Files (x86)\Sybase\EAServer6\genfiles\java\classes;

    I tried tweking the stack size and heap parameters to get out of the issue but it has been of no use.

    I could see that you also advised to include the max process per user, but no idea how and where I need to add this parameter value ?

    Do you have any suggestion or info how I can proceed to fix the running issue in EAServer6.



    1. Hi Kunal,
      This post is specific to linux/unix as windows has a different threading model. I don't recall seeing this error before on windows but it could just be a standard out of heap space. Yours is only set to 512M, for win32 you can typically go as high as 1200M.

      Also, for windows specific options see:

      But you'd likely find the solution on sybase's website.

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