What are the -Xms and -Xmx parameters when starting JVM?

100    Asked by CharlesParr in Java , Asked on Nov 2, 2023

  Please explain the use of the Xms and Xmx parameters in JVMs. What are the default values for them?

Answered by Unnati gautam

The Xms and Xmx are parameters that are used in Java Virtual Machines (JVMs). These are used to define the initial and maximum heap sizes. Heal sizes refer to the allocated memory in your device's Random Access Memory( RAM), which is specially dedicated to running Java programs. In the context of JVM, the heap is the area where data are stored during the program execution. 

Xms sets the initial heap size for Java virtual machines(JVM) will divide whenever it starts. 

On the other hand, Xms sets the maximum heap size that the Java virtual machines (JVM) can reach whenever it executes. One thing you should remember is that the default values for these parameters can vary. Its parameters decide on the operating system (OS), Java Implementation, and platforms. However, in the current scenario, the default value for both Xms and Xmx are the same for both. 

Generally, in some cases, the values are set as around 1/4th of the physical memory. If you want to check your default values for Xms and Xmx on your Java virtual machines (JVM) then you can use the “java- xx:+ PrintFlagsFinal” command. It will display the default setting for your Java virtual machine parameters.

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