Increasing Java Heap Size - java

I'm trying to increase value of heap size of my jvm, but it doesn't work. Could anybody help me with this geek problem?
My configuration are follow: Windows 7 x64, 4 GB, i3 CPU
When I try something like -Xmx2000M I have nothing
Where are my errors?

I think you are expecting this.
$ java -Xmx2000M -Xms1000M -XshowSettings:all
VM settings:
Min. Heap Size: 1000.00M
Max. Heap Size: 1.95G
Ergonomics Machine Class: server
Using VM: Java HotSpot(TM) 64-Bit Server VM

Your command is half correct. You need to specify what you want to run with an increased heap size. Something like this
java -Xmx2000M -Xms1000M -jar <jar-file-name>.jar

you need to specify as well which class/jar you want to run. You cannot just increase the heap size per default for all java pplications. Instead you have to edit the command line of the program you are trying to run.

The error you have got in the last screen shot is about unavailability of the class file to run.
You should provide class file which includes main function while running java command.
java -Xmx2000M -Xms1000m MyClass
Considering you have MyClass.class in your classpath.

You need to provide something for JVM to run with these new settings.
The arguments you are using only configure the JVM, it still needs whatever jar or class file you want to run.
To permanently configure JVM profile on windows, follow these Instructions. The settings tool will let you edit runtime parameters:

may be I am late)
But I think you can use it. In IDEA choose Edit Configuration... on drop-down list(look on picture below). And then type in VM Options your parameters -Xmx2000M -Xms1000M.
How to find Edit Configuration on IDEA

Related

How to get Java to give Alloy more memory

I am using alloy4.2, and I am not able to tell it to use more memory.
I am not a Java expert and I suspect the problem is in how I'm configuring Java.
I am using OpenJDK Runtime Environment 1.8.0_131.
I have also tried 1.8.0_151.
My VM is running in Ubuntu x64.
Under the Alloy Options tab, Maximum Memory To Use is always stuck at the default of 768M.
I am using a VM that has 16G of memory available.
I have tried setting the Java stack parameters
-Xms1g and -Xmx8g
at the command line when I invoke Java, and also using the "export _JAVA_OPTS" to no avail.
Java says it is "picking up" the Xms and Xmx values and when I run
Java -XshowSettings:vm it shows that I have a max heap size of approx. 7.9G.
But Alloy doesn't let me increase the memory beyond the tiny minimum size of 768M. Any idea what I am doing wrong?
The numbers are hardcoded in Alloy although 4.2 should have 4Gb included? (There are a number of variants of 4.2 out there I think.)
We're working on creating a 5.0.0 version at the moment but that is not really publishable yet. You can download a snapshot JAR from:
https://oss.sonatype.org/content/repositories/snapshots/org/alloytools/org.alloytools.alloy.dist/5.0.0-SNAPSHOT/

error: could not find or load main class java after updating -Xss Eclipse

I have tried all the recommended solutions for this but I can't manage to fix it. After going to Run / Run configurations / Arguments and writing in the VM Arguments section "java -Xss2048m" I get the error:
error: could not find or load main class java
How can I fix this?
Remove the java. The VM Arguments section only contains the arguments and not the Java command.
I'm not familiar with -Xss. I didn't see it in the docs for JVM options by Oracle.
If you're trying to set initial and max heap sizes, shouldn't that be -Xms or -Xmx?
Do you have a 64 bit operating system and 64 bit JVM? If not, you won't be able to get more than 1.7 GB heap.

How to increase heap memory for WildFly?

WildFly 8 is started on a linux server with standalone.sh. I noticed that the server was started with very few heap memory space.
I need to increase the heap memory space for the server and for applications, which are running on the server. How can I do it?
Just edit bin/standalone.conf, look for the first occurrence of JAVA_OPTS and change the -Xmx option according to your needs.
Linux:
bin/standalone.conf
Check for the following line,
JAVA_OPTS
and change it accordingly to suit your heap size needs
-Xms1303m: initial heap size in megabytes
-Xmx1303m: maximum heap size in megabytes
JAVA_OPTS="-Xms1024M -Xmx2048M -XX:MaxPermSize=2048M -XX:MaxHeapSize=2048M"
Windows:
bin/standalone.conf.bat
JAVA_OPTS="-Xms1024M -Xmx2048M -XX:MaxPermSize=2048M -XX:MaxHeapSize=2048M"
Now restart the server and it will work without prompting any heap size errors.
On OS WINDOWS you need to setting standalone.conf.bat
if wildfly 8 is used along with JDK 8,
We need to add MaxMetaSpace Size.
For example,
JAVA_OPTS="$JAVA_OPTS -XX:MaxMetaspaceSize=256M"
As we all know Java 8 does not support Perm gen setting.
For related information, Please check
Wildfly Heap issue
I hope it helps.
I am running Eclipse and changing the 'bin/standalone.conf' didn’t work for me. In this case the solution was oppening the 'Servers' view in Eclipse, double-click the Wildfly server, go to 'Open launch configuation' and do that changes there in 'VM argumments'. Anyway I am a bit noob with Wildfly, I hope other users could contrast my info, I found that in http://www.nailedtothex.org/roller/kyle/entry/articles-wildfly-jvmparams
Its for a Linux server, but I think it could work for windows too.
For managed domain you can set it using heap tag (e.g.<heap size="64m" max-size="512m"/>) within jvm in domain.xml or host.xml (depending on the scope you want to address).
Answer from official documentation:
For a standalone server, you have to pass in the JVM settings either
as command line arguments when executing the
$JBOSS_HOME/bin/standalone.sh script, or by declaring them in
$JBOSS_HOME/bin/standalone.conf. (For Windows users, the script to
execute is %JBOSS_HOME%/bin/standalone.bat while the JVM settings can
be declared in %JBOSS_HOME%/bin/standalone.conf.bat)
** Restart server to make this change effective.

Could not create the Java virtual machine

facing some problem with java virtual machine initialization. when i am using root account i can properly work with java. but when i am a user account it returns following errors
user#host# $JAVA_HOME/bin/java -version
Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.
It does not seems like a memory issue as the same command works with root account. Available memory (free -m) is more than 1200MB
Also i have tried increasing the JVM memory limits
Just be careful. You will get this message if you try to enter a command that doesn't exist, e.g.:
/usr/bin/java -v
I had this issue today, and for me the problem was that I had allocated too much memory:
-Xmx1024M -XX:MaxPermSize=1024m
Once I reduced the PermGen space, everything worked fine:
-Xmx1024M -XX:MaxPermSize=512m
I know that doesn't look like much of a difference, but my machine only has 4GB of RAM, and apparently that was the straw that broke the camel's back. The Java VM was failing immediately upon every action because it was failing to allocate the memory.
Set the JVM memory:
export _JAVA_OPTIONS=-Xmx512M
The problem got resolved when I edited the file /etc/bashrc with same contents as in /etc/profiles and in /etc/profiles.d/limits.sh and did a re-login.
Make sure the physical available memory is more then VM defined min/max memory.

Could not reserve enough space for object heap

I am getting the following exception repeatedly each time I try to run the program.
Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.
I tried to increase my virtual memory (page size) and RAM size, but to no avail.
How can I eliminate this error?
Run the JVM with -XX:MaxHeapSize=512m (or any big number as you need) (or -Xmx512m for short)
This can also be caused by setting something too large on a 32-bit HotSpot vm, for example:
-Xms1536m -Xmx1536m
where this might/would work:
-Xms1336m -Xmx1336m
here is how to fix it:
Go to Start->Control Panel->System->Advanced(tab)->Environment Variables->System
Variables->New: Variable name: _JAVA_OPTIONS
Variable value: -Xmx512M
Variable name: Path
Variable value: %PATH%;C:\Program Files\Java\jre6\bin;F:\JDK\bin;
Change this to your appropriate path.
I ran into this when using javac, and it doesn't seem to pick up on the command line options,
-bash-3.2$ javac -Xmx256M HelloWorldApp.java
Error occurred during initialization of VM
Could not reserve enough space for object heap
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
so the solution here it so set _JAVA_OPTIONS
-bash-3.2$ export _JAVA_OPTIONS="-Xmx256M"
-bash-3.2$ javac HelloWorldApp.java
Picked up _JAVA_OPTIONS: -Xmx256M
And this compiles fine.
This happens to me on machines with a lot of RAM, but with lower memory ulimits. Java decides to allocate a big heap because it detects the ram in the machine, but it's not allowed to allocate it because of ulimits.
32-bit Java requires contiguous free space in memory to run. If you specify a large heap size, there may not be so much contiguous free space in memory even if you have much more free space available than necessary.
Installing a 64-bit version of Java helps in these cases, the contiguous memory requirements only applies to 32-bit Java.
Combined with -Xmx512M use -d64 to make sure you're running 64-bit VM. On a 64-bit machine I thought for sure I was running 64-bit virtual machine, but no. After installing 64-bit Java the -d64 option works and -Xmx allows much larger memory sizes.
java -d64 -Xmx512M mypackage.Test
Open gradle.properties file in android folder.
Replace this line:
org.gradle.jvmargs=-Xmx1536M
with:
org.gradle.jvmargs=-Xmx512m
Explanation:
Max limit from Gradle document:
If the requested build environment does not specify a maximum heap size, the Daemon will use up to 512MB of heap.
I got the same error and resolved this by configuring it in the run.conf.bat
Run the JVM with the configuring run.conf.bat in Jboss5x
If free memory is not available AS you are passing in the statement then please make changes in run.conf.bat
set "JAVA_OPTS=-Xms512m -Xmx512m -XX:MaxPermSize=256m"
I had similar issues. I had installed 32 bit version of Java on a 64 bit machine.
By uninstalling that version and installing 64 bit version of Java. I was able to resolve the issue.
I know there are a lot of answers here already, but none of them helped me. In the end I opened the file /etc/elasticsearch/jvm.options and changed:
-Xms2G
-Xmx2G
to
-Xms256M
-Xmx256M
That solved it for me. Hopefully this helps someone else here.
Suppose your class is called Test in package mypackage. Run your code like this:
java -Xmx1024m mypackage.Test
This will reserve 1024 MB of heap space for your code. If you want 512 MB, you can use:
java -Xmx512m mypackage.Test
Use little m in 1024m, 512m, etc
Sometimes, this error indicates that physical memory and swap on the server actually are fully utilized!
I was seeing this problem recently on a server running RedHat Enterprise Linux 5.7 with 48 GB of RAM. I found that even just running
java -version
caused the same error, which established that the problem was not specific to my application.
Running
cat /proc/meminfo
reported that MemFree and SwapFree were both well under 1% of the MemTotal and SwapTotal values, respectively:
MemTotal: 49300620 kB
MemFree: 146376 kB
...
SwapTotal: 4192956 kB
SwapFree: 1364 kB
Stopping a few other running applications on the machine brought the free memory figures up somewhat:
MemTotal: 49300620 kB
MemFree: 2908664 kB
...
SwapTotal: 4192956 kB
SwapFree: 1016052 kB
At this point, a new instance of Java would start up okay, and I was able to run my application.
(Obviously, for me, this was just a temporary solution; I still have an outstanding task to do a more thorough examination of the processes running on that machine to see if there's something that can be done to reduce the nominal memory utilization levels, without having to resort to stopping applications.)
Error :
For the error, "error occurred during initialization of vm could not reserve enough space for object heap jboss"
Root Cause :
Improper/insufficient memory allocation to our JVM as mentioned below.
e.g. JAVA_OPTS="-Xms1303m -Xmx1303m -XX:MaxPermSize=256m" in jboss-eap-6.2\bin\standalone.conf or "JAVA_OPTS=-Xms1G -Xmx1G -XX:MaxPermSize=256M" in jboss-eap-6.2\bin\standalone.conf.bat which is nothing but JVM memory allocation pool parameters.
Resolution :
Increase the heap size. To increase the heap size,
goto -> jboss-eap-6.2\bin\standalone.conf.bat or jboss-eap-6.2\bin\standalone.conf
change ->JAVA_OPTS="-Xms256m -Xmx512m -XX:MaxPermSize=256m" where -Xms is Minimum heap size and -Xmx is Maximum heap size.
Usually its not recommanded to have same size for min and max.
If you are running your application from eclipse,
Double click on the server
select 'open launch configuration' you will be redirected to the window 'Edit launch configuration properties'.
In this windown goto the tab '(x)=Arguments'.
In VM Arguments, define your heap size as mentioned below
"-Dprogram.name=JBossTools: JBoss EAP 6.1+ Runtime Server" -server -Xms256m -Xmx512m -XX:MaxPermSize=256m -Dorg.jboss.resolver.warning=true
I recently faced this issue. I have 3 java applications that start with 1024m or 1280m heap size.
Java is looking at the available space in swap, and if there is not enough memory available, the jvm exits.
To resolve the issue, I had to end several programs that had a large amount of virtual memory allocated.
I was running on x86-64 linux with a 64-bit jvm.
I had right amount of memory settings but for me it was using a 64bit intellij with 32 bit jvm. Once I switched to 64 bit VM, the error was gone.
If you're running 32bit JVM, change heap size to smaller would probabaly help. You can do this by passing args to java directly or through enviroment variables like following,
java -Xms128M -Xmx512M
JAVA_OPTS="-Xms128M -Xmx512M"
For 64bit JVM, bigger heap size like -Xms512M -Xmx1536M should work.
Run java -version or java -d32, java--d64 for Java7 to check which version you're running.
Assuming you have enough free memory and you setup you JVM arguments correctly, you might have a problem of memory fragmentation. Check Java maximum memory on Windows XP.
Anyway, here is how to fix it:
Go to Start->Control Panel->System->Advanced(tab)->Environment Variables->System Variables->New:
Variable name: _JAVA_OPTIONS
Variable value: -Xmx512M
OR
Change the ant call as shown as below.
<exec
**<arg value="-J-Xmx512m" />**
</exec>
It worked for me.
Error occurred during initialization of VM
Could not reserve enough space for 1572864KB object heap
I changed value of memory in settings.grade file
1536 to 512 and it helped
Go to Start->Control Panel->System->Advanced(tab)->Environment Variables->System Variables->New:
Variable name: _JAVA_OPTIONS
Variable value: -Xmx512M
In case you are running a java program:
- run your program in a terminal using the correct command for linux it would be 'java -jar myprogram.jar' and add -Xms256m -Xmx512m, for instance: 'java -jar myprogram.jar Xms256m -Xmx512m'
In case you are running a .sh script (linux, mac?) or a .bat script (windows) open the script and look for the java options if they are present and increase the memory.
If all of the above doesn't work, check your processes (ctrl+alt+delete on windows) (ps aux on linux/mac) and kill the processes which use allot of memory and are not necessary for your operating system! => Try to re-run your program.
In CASSANDRA_HOME/bin/cassandra.bat you would find following configuration
REM JVM Opts we'll use in legacy run or installation
set JAVA_OPTS=-ea^
-javaagent:"%CASSANDRA_HOME%\lib\jamm-0.3.0.jar"^
-Xms**2G**^
-Xmx**2G**^
You can reduce 2G to some smaller number for e.g. 1G or even lesser and it should work.
Same if you are running on unix box, change in .sh file appropriately.
I got the same error and it got resolved when I deleted temp files using %temp% and restarting eclipse.
Sometimes it relates as
$ sysctl vm.overcommit_memory
vm.overcommit_memory = 2
If you set it to:
$ sysctl vm.overcommit_memory=0
It should work.
Replace -Xmx2G with -Xms512M or any greater memory size in cassandra.bat file in cassandra bin directory.
In my case I couldn't increase org.gradle.jvmargs=-Xmx... in gradle.properties beyond 1GB. It didn't work because I had two Java installation on my machine, one 32 bit (Gradle was using this one) and the other 64 bit. I resolved the problem by adding JAVA_HOME environment variable pointing to 64 bit Java.
No need to do anything just chnage in POM file like below
<configuration>
<maxmemory>1024M</maxmemory>
</configuration>

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