String build() {
            if (legacyOptions)
                return buildLegacyOptions();

            Element jvmElement = XML.getChild(nodesElement, "jvm");
            if (jvmElement == null) return "";
            String jvmOptions = jvmElement.getAttribute(VespaDomBuilder.OPTIONS);
            if (jvmOptions.isEmpty()) return "";
            validateJvmOptions(jvmOptions);
            return jvmOptions;
        }
Validates JVM options and logs a warning or fails deployment (depending on feature flag)
if anyone of them has invalid syntax or is an option that is unsupported for the running system.
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java