JVM Args
The following JVM Args are supported when starting the embedded server.

heapSize

You can set the max heap size the server is allowed to have (-Xmx) by passing the heapSize parameter to the start command. This parameter defaults to megabytes but you can specify any valid suffix.
start heapSize=1024
In server.json
server set JVM.heapSize=1024
server set JVM.heapSize=2G
server show JVM.heapSize

minHeapSize

You can set the starting heap size for the server (-Xms) by passing the minHeapSize parameter to the start command. This parameter defaults to megabytes but you can specify any valid suffix.
start minHeapSize=1024
In server.json
server set JVM.minHeapSize=1024
server set JVM.minHeapSize=2G
server show JVM.minHeapSize

Ad Hoc JVM Args

You can specify ad-hoc JVM args for the server with the JVMArgs parameter.
start JVMArgs="-XX:MaxGCPauseMillis\=200"
In server.json
server set JVM.args="-XX:MaxGCPauseMillis\=200"
server show JVM.args
JVM args can also be set an array of strings which prevents you from needing to escape or quote anything.
{
"jvm" : {
"args" : [
"-XX:+UseG1GC",
"-XX:-CreateMinidumpOnCrash",
"--add-opens=java.base/java.net=ALL-UNNAMED"
]
}
}
Or via the CLI like so:
server set jvm.args=["-XX:+UseG1GC"]
server set jvm.args=["-XX:-CreateMinidumpOnCrash"] --append
server set jvm.args=["--add-opens=java.base/java.net=ALL-UNNAMED"] --append

Ad Hoc Runwar Options

You can specify ad-hoc options for the underlying Runwar library using the RunwarArgs parameter.
start RunwarArgs="--sendfile-enable false"
In server.json
server set runwar.args="--sendfile-enable false"
server show runwar.args
Runwar args can also be set an array of strings which prevents you from needing to escape or quote anything.
{
"runwar" : {
"args" : [
"--runwar-option",
"value",
"--runwar-option2",
"value2"
]
}
}
Or via the CLI like so:
server set runwar.args=["--runwar-option","value"]
server set runwar.args=["--runwar-option2","value2"] --append