Use the java_vm_options option to specify any additional command line options that are required to start the Java virtual machine (VM).
Use this syntax:
SET OPTION PUBLIC.java_vm_options='java-options';
In the following example, you use java_vm_options to set the maximum heap size of the Java VM to 512 megabytes:
SET OPTION PUBLIC.java_vm_options='-Xmx512m';
In the following example, you set the initial heap size of the Java VM to 32 megabytes:
SET OPTION PUBLIC.java_vm_options='-Xms32m';