Using -X command-line options

Use these options to configure the OpenJ9 virtual machine (VM). Unlike standard options, options prefixed with -X are nonstandard and are typically unique to a Java™ virtual machine implementation. However, in some cases, -X option names are common to different VM implementations and might have the same function.

For options that take a <size> parameter, suffix the number with "k" or "K" to indicate kilobytes, "m" or "M" to indicate megabytes, or "g" or "G" to indicate gigabytes.

For example, to set the -Xmx value to 16 MB, you can specify -Xmx16M, -Xmx16m, -Xmx16384K, -Xmx16384k, or -Xmx16777216 on the command line.