How to increase Java heap space for a tomcat app

Question

There are lots of questions that ask this or a similar question   They all give the command that has to be executed  what I don t understand is where do I write this command  I want to permanently increase the heap space for my tomcat apps   I read this page http   javahowto blogspot com 2006 06 6-common-errors-in-setting-java-heap html and it says under the Tomcat section      Stop Tomcat server  set environment variable CATALINA OPTS  and then restart Tomcat  Look at the file tomcat-install bin catalina sh or catalina bat for how this variable is used  For example       set CATALINA OPTS -Xms512m -Xmx512m   Windows  no    around the value    export CATALINA OPTS  -Xms512m -Xmx512m    ksh bash     around the value    setenv CATALINA OPTS  -Xms512m -Xmx512m    tcsh csh     around the value    So I replaced the line      set CATALINA OPTS     with      set CATALINA OPTS -Xms512m -Xmx512m     But I still get the error      javax servlet ServletException  Servlet execution threw an exception      root cause      java lang OutOfMemoryError  Java heap space       java lang reflect Array multiNewArray Native Method        java lang reflect Array newInstance Array java 90        nom tam util ArrayFuncs newInstance ArrayFuncs java 1028        nom tam fits ImageData read ImageData java 259        nom tam fits Fits readHDU Fits java 573        controller UploadServlet retreiveFITSFileFields UploadServlet java 206        controller ScanServerFiles doPost ScanServerFiles java 39        javax servlet http HttpServlet service HttpServlet java 637        javax servlet http HttpServlet service HttpServlet java 717

User · Answer

First of all you cannot change the memory settings only for a tomcat application but rather for all tomcat instance.

If you are running tomcat from console (using startup.bat) you'll need to edit catalina.bat and play around with CATALINA_OPTS. For example:

set CATALINA_OPTS=-Xms512m -Xmx512m

Restarting tomcat will apply the new settings.

If you are still getting OutOfMemoryError you need to know how much memory does your application need at that particular moment (nom.tam.util.ArrayFuncs...). You'll either have to optimize the application or simply increase the memory provided to tomcat.

User · Answer

Your change may well be working  Does your application need a lot of memory - the stack trace shows some Image related features   I m guessing that the error either happens right away  with a large file  or happens later after several requests    If the error happens right away  then you can increase memory still further  or investigate find out why so much memory is needed for one file   If the error happens after several requests  then you could have a memory leak - where objects are not being reclaimed by the garbage collector  Using a tool like JProfiler can help you monitor how much memory is being used by your VM and can help you see what is using that memory and why objects are not being reclaimed by the garbage collector

User · Answer

Just set this extra line in catalina bat  file   LINE NO AROUND  143  set  CATALINA OPTS -Xms512m -Xmx512m    And restart Tomcat service

User · Answer

For Windows Service  you need to run tomcat9w exe  or 6w 7w 8w  depending on your version of tomcat  First  make sure tomcat is stopped   Then double click on tomcat9w exe   Navigate to the Java tab   If you know you have 64 bit Windows with 64 bit Java and 64 bit Tomcat  then feel free to set the memory higher than 512   You ll need to do some task manager monitoring to determine how high to set it   For most apps developed in 2019    I d recommend an initial memory pool of 1024  and the maximum memory pool of 2048   Of course if your computer has tons of RAM    feel free to go as high as you want  Also  see this answer  How to increase Maximum Memory Pool Size  Apache Tomcat 9

User · Answer

There is a mechanism to do it without modifying any files that are in the distribution  You can create a separate file  CATALINA HOME  bin setenv bat or  CATALINA HOME bin setenv sh and put your environment variables there  Further  the memory settings apply to the JVM  not Tomcat  so I d set the JAVA OPTS variable instead   set JAVA OPTS -Xmx512m

User · Answer

Open the server tab in eclipse right click open click on open lauch configuration Go to arguments Here you can add in VM arguments after endorsed   -Xms64m -Xmx256m

User · Answer

you can set this in catalina sh as CATALINA OPTS -Xms512m -Xmx512m  Open your tomcat-dir bin catalina sh file and add following line anywhere -   CATALINA OPTS   CATALINA OPTS -Xms1024m -Xmx3024m    and restart your tomcat

User · Answer

if you are using Windows  it s very simple  Just go to System Environnement variables  right-clic Computer   Properties   Advanced System Parameters   Environnement Variables   create a new system variable with name   CATALINA OPTS and value   -Xms512m -Xmx1024m  restart Tomcat and enjoy

User · Answer

You need to add the following lines in your catalina sh file   export CATALINA OPTS  -Xms512M -Xmx1024M    UPDATE   catalina sh content clearly says -     Do not set the variables in this script  Instead put them into a script   setenv sh in CATALINA BASE bin to keep your customizations separate    So you can add above in setenv sh instead  create a file if it does not exist

User · Answer

Easiest way of doing is   In Linux Ububuntu e t c   Go to tomcat bin directory   cd  opt tomcat8 5 bin   create new file under bin directory  setenv sh  and save below mention entries in it   export CATALINA OPTS   CATALINA OPTS -Xms512m  export CATALINA OPTS   CATALINA OPTS -Xmx2048m  export CATALINA OPTS   CATALINA OPTS -XX MaxPermSize 256m    and issue command     catalina sh run   In your catalina log file you can see entry like this   INFO  main  VersionLoggerListener log Command line argument  -Xms512m INFO  main  VersionLoggerListener log Command line argument  -Xmx2048m INFO  main  VersionLoggerListener log Command line argument  -XX MaxPermSize 256m   Which confirms that above changes took place    Also  the value of  Xms512m  and  -Xmx2048m  can be modified accordingly in the setenv sh file   Startup of tomcat could be done in two steps as well   cd  opt tomcat8 5 bin  Step  1 run   setenv sh  Step  2   startup sh   If you re using systemd edit    usr lib systemd system tomcat8 service   and set   Environment CATALINA OPTS  -Xms512M -Xmx2048M -XX MaxPermSize 256m

[java] How to increase Java heap space for a tomcat app

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