How to solve java io IOException error 12 Cannot allocate memory calling Runtime exec

Question

On my system I can t run a simple Java application that start a process  I don t know how to solve    Could you give me some hints how to solve   The program is    root newton sisma-acquirer   cat prova java import java io IOException   public class prova       public static void main String   args  throws IOException           Runtime getRuntime   exec  ls               The result is    root newton sisma-acquirer   javac prova java  amp  amp  java -cp   prova Exception in thread  main  java io IOException  Cannot run program  ls   java io IOException  error 12  Cannot allocate memory         at java lang ProcessBuilder start ProcessBuilder java 474          at java lang Runtime exec Runtime java 610          at java lang Runtime exec Runtime java 448          at java lang Runtime exec Runtime java 345          at prova main prova java 6  Caused by  java io IOException  java io IOException  error 12  Cannot allocate memory         at java lang UNIXProcess  lt init gt  UNIXProcess java 164          at java lang ProcessImpl start ProcessImpl java 81          at java lang ProcessBuilder start ProcessBuilder java 467              4 more   Configuration of the system    root newton sisma-acquirer   java -version java version  1 6 0 0  OpenJDK Runtime Environment  IcedTea6 1 5   fedora-18 b16 fc10-i386  OpenJDK Client VM  build 14 0-b15  mixed mode   root newton sisma-acquirer   cat  etc fedora-release Fedora release 10  Cambridge    EDIT  Solution  This solves my problem  I don t know exactly why   echo 0    proc sys vm overcommit memory  Up-votes for who is able to explain     Additional informations  top output    top - 13 35 38 up 40 min   2 users   load average  0 43  0 19  0 12 Tasks  129 total    1 running  128 sleeping    0 stopped    0 zombie Cpu s    1 5 us   0 5 sy   0 0 ni  94 8 id   3 2 wa   0 0 hi   0 0 si   0 0 st Mem    1033456k total    587672k used    445784k free     51672k buffers Swap   2031608k total         0k used   2031608k free    188108k cached   Additional informations  free output     root newton sisma-acquirer   free              total       used       free     shared    buffers     cached Mem        1033456     588548     444908          0      51704     188292 -   buffers cache      348552     684904 Swap       2031608          0    2031608

User · Answer

This is the solution but you have to set   echo 1  gt   proc sys vm overcommit memory

User · Answer

I came across these links   http   mail openjdk java net pipermail core-libs-dev 2009-May 001689 html  http   www nabble com Review-request-for-5049299-td23667680 html  Seems to be a bug  Usage of a spawn   trick instead of the plain fork   exec   is advised

User · Answer

overcommit memory  Controls overcommit of system memory  possibly allowing processes to allocate  but not use  more memory than is actually available   0 - Heuristic overcommit handling  Obvious overcommits of address space are refused  Used for a typical system  It ensures a seriously wild allocation fails while allowing overcommit to reduce swap usage  root is allowed to allocate slighly more memory in this mode  This is the default   1 - Always overcommit  Appropriate for some scientific applications   2 - Don t overcommit  The total address space commit for the system is not permitted to exceed swap plus a configurable percentage  default is 50  of physical RAM  Depending on the percentage you use  in most situations this means a process will not be killed while attempting to use already-allocated memory but will receive errors on memory allocation as appropriate

User · Answer

I solved this using JNA  https   github com twall jna  import com sun jna Library  import com sun jna Native  import com sun jna Platform   public class prova        private interface CLibrary extends Library           CLibrary INSTANCE    CLibrary  Native loadLibrary  Platform isWindows      msvcrt     c    CLibrary class           int system String cmd              private static int exec String command            return CLibrary INSTANCE system command              public static void main String   args            exec  ls

User · Answer

If you look into the source of java lang Runtime  you ll see exec finally call protected method  execVM  which means it uses Virtual memory  So for Unix-like system  VM depends on amount of swap space   some ratio of physical memory   Michael s answer did solve your problem but it might  or to say  would eventually  cause the O S  deadlock in memory allocation issue since 1 tell O S  less careful of memory allocation  amp  0 is just guessing  amp  obviously that you are lucky that O S  guess you can have memory THIS TIME  Next time  Hmm       Better approach is that you experiment your case  amp  give a good swap space  amp  give a better ratio of physical memory used  amp  set value to 2 rather than 1 or 0

User · Answer

Runtime getRuntime   exec allocates the process with the same amount of memory as the main  If you had you heap set to 1GB and try to exec then it will allocate another 1GB for that process to run

User · Answer

This is solved in Java version 1 6 0 23 and upwards   See more details at http   bugs sun com bugdatabase view bug do bug id 7034935

User · Answer

What s the memory profile of your machine   e g  if you run top  how much free memory do you have    I suspect UnixProcess performs a fork   and it s simply not getting enough memory from the OS  if memory serves  it ll fork   to duplicate the process and then exec   to run the ls in the new memory process  and it s not getting as far as that   EDIT  Re  your overcommit solution  it permits overcommitting of system memory  possibly allowing processes to allocate  but not use  more memory than is actually available  So I guess that the fork   duplicates the Java process memory as discussed in the comments below  Of course you don t use the memory since the  ls  replaces the duplicate Java process

User · Answer

As weird as this may sound  one work around is to reduce the amount of memory allocated to the JVM  Since fork   duplicates the process and its memory  if your JVM process does not really need as much memory as is allocated via -Xmx  the memory allocation to git will work   Of course you can try other solutions mentioned here  like over-committing or upgrading to a JVM that has the fix   You can try reducing the memory if you are desperate for a solution that keeps all software intact with no environment impact  Also keep in mind that reducing -Xmx aggressively can cause OOMs  I d recommend upgrading the JDK as a long-term stable solution

User · Answer

You can use the Tanuki wrapper to spawn a process with POSIX spawn instead of fork  http   wrapper tanukisoftware com doc english child-exec html     The WrapperManager exec   function is an alternative to the Java-Runtime exec   which has the disadvantage to use the fork   method  which can become on some platforms very memory expensive to create a new process

[java] How to solve "java.io.IOException: error=12, Cannot allocate memory" calling Runtime#exec()?

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