It varies on implementation and version, but usually it depends on the VM used (e.g. client or server, see -client and -server parameters) and on your system memory.
Often for client the default value is 1/4th of your physical memory or 1GB (whichever is smaller).
Also Java configuration options (command line parameters) can be "outsourced" to environment variables including the -Xmx, which can change the default (meaning specify a new default). Specifically the JAVA_TOOL_OPTIONS environment variable is checked by all Java tools and used if exists (more details here and here).
You can run the following command to see default values:
java -XX:+PrintFlagsFinal -version
It gives you a loooong list, -Xmx is in MaxHeapSize, -Xms is in InitialHeapSize. Filter your output (e.g. |grep on linux) or save it in a file so you can search in it.
memory - What is the default max heap size (-Xmx) in Java 8? - Stack Overflow
Adjust default max heap size when running in container
java - Runtime heap size set in Eclipse - Stack Overflow
jvm - How to increase application heap size in Eclipse? - Stack Overflow
It varies on implementation and version, but usually it depends on the VM used (e.g. client or server, see -client and -server parameters) and on your system memory.
Often for client the default value is 1/4th of your physical memory or 1GB (whichever is smaller).
Also Java configuration options (command line parameters) can be "outsourced" to environment variables including the -Xmx, which can change the default (meaning specify a new default). Specifically the JAVA_TOOL_OPTIONS environment variable is checked by all Java tools and used if exists (more details here and here).
You can run the following command to see default values:
java -XX:+PrintFlagsFinal -version
It gives you a loooong list, -Xmx is in MaxHeapSize, -Xms is in InitialHeapSize. Filter your output (e.g. |grep on linux) or save it in a file so you can search in it.
Like you have mentioned, The default -Xmxsize (Maximum HeapSize) depends on your system configuration.
Java8 client takes Larger of 1/64th of your physical memory for your Xmssize (Minimum HeapSize) and Smaller of 1/4th of your physical memory for your -Xmxsize (Maximum HeapSize).
Which means if you have a physical memory of 8GB RAM, you will have Xmssize as Larger of 8*(1/64) and Smaller of -Xmxsizeas 8*(1/4).
You can Check your default HeapSize with
In Windows:
java -XX:+PrintFlagsFinal -version | findstr /i "HeapSize PermSize ThreadStackSize"
In Linux:
java -XX:+PrintFlagsFinal -version | grep -iE 'HeapSize|PermSize|ThreadStackSize'
These default values can also be overrided to your desired amount.
In the run configuration you want to customize (just click on it) open the tab Arguments and add -Xmx2048min the VM arguments section.
You might want to set the -Xms as well (small heap size).
Go to Eclipse Folder
Find Eclipse Icon in Eclipse Folder
Right Click on it you will get option "Show Package Content"
Contents folder will open on screen
If you are on Mac then you'll find "MacOS"
Open MacOS folder you'll find eclipse.ini file
Open it in word or any file editor for edit
...
-XX:MaxPermSize=256m -Xms40m -Xmx512m...
Replace -Xms512m to -Xmx1024m
Save the file and restart your Eclipse
Have a Nice time :)
It is possible to increase heap size allocated by the Java Virtual Machine (JVM) by using command line options.
-Xms<size> set initial Java heap size
-Xmx<size> set maximum Java heap size
-Xss<size> set java thread stack size
If you are using the tomcat server, you can change the heap size by going to Eclipse/Run/Run Configuration and select Apache Tomcat/your_server_name/Arguments and under VM arguments section use the following:
-XX:MaxPermSize=256m
-Xms256m -Xmx512M
If you are not using any server, you can type the following on the command line before you run your code:
java -Xms64m -Xmx256m HelloWorld
More information on increasing the heap size can be found here
You can use this configuration:
-startup
plugins/org.eclipse.equinox.launcher_1.3.0.v20120522-1813.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20120913-144807
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-vmargs
-Xms512m
-Xmx1024m
-XX:+UseParallelGC
-XX:PermSize=256M
-XX:MaxPermSize=512M