How to extend java memory ?

Small info on Memory increase in java.

By using the command Xms and Xmx ,we can increase the java memory .

The flag Xmx specifies the maximum memory allocation pool for a Java Virtual Machine (JVM), while Xms specifies the initial memory allocation pool.

This means that your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of memory. For example, starting a JVM like below will start it with 256MB of memory, and will allow the process to use up to 2048MB of memory:

java -Xmx2048m -Xms256m

The memory flag can also be specified in multiple sizes, such as kilobytes, megabytes, and so on.

-Xmx1024k

-Xmx512m

-Xmx8g

The Xms flag has no default value, and Xmx typically has a default value of 256MB. A common use for these flags is when you encounter a java.lang.OutOfMemoryError.

To aovoid "java.lang.OutOfMemoryError: PermGen space” error,have to use "-XX:MaxPermSize=256m"  .

*Here k-KB,m-MB,g-GB

*If we are using any IDE(Netbean or Eclipse) then have to add in VM optios for core application.

*For Web application have to add stanalone.conf(Wildfly server bin folder) and catlina.sh or catlina.bat (tomcat bin folder) like below :

JAVA_OPTS="-Xms64m -Xmx512m -XX:MaxPermSize=256m