MemoryUtil's static constructor call to ManagementFactory.getMemoryPoolMXBeans() fails on Google App Engine

    [INFO] java.lang.NoClassDefFoundError: java.lang.management.ManagementFactory is a restricted class. Please see the Google  App Engine developer's guide for more details.

    [INFO]  at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:52)

    [INFO]  at org.drools.core.util.MemoryUtil.<clinit>(MemoryUtil.java:33)

    [INFO]  at java.lang.Class.forName0(Native Method)

    [INFO]  at java.lang.Class.forName(Class.java:195)

    [INFO]  at com.google.appengine.tools.development.agent.runtime.RuntimeHelper.checkRestricted(RuntimeHelper.java:70)

    [INFO]  at com.google.appengine.tools.development.agent.runtime.Runtime.checkRestricted(Runtime.java:65)

    [INFO]  at org.drools.core.RuleBaseConfiguration.setPermGenThreshold(RuleBaseConfiguration.java:583)

    [INFO]  at org.drools.core.RuleBaseConfiguration.init(RuleBaseConfiguration.java:451)

    [INFO]  at org.drools.core.RuleBaseConfiguration.init(RuleBaseConfiguration.java:429)

    [INFO]  at org.drools.core.RuleBaseConfiguration.<init>(RuleBaseConfiguration.java:278)

    [INFO]  at org.drools.compiler.kie.builder.impl.KieServicesImpl.newKieBaseConfiguration(KieServicesImpl.java:185)

    static {
        if (!hasPermGen() || ClassUtils.isAndroid()) { // hasPermGen is true because GAE doesn't support java 8 yet
            permGenStats = new DummyMemoryStats();
        } else {
            MemoryPoolMXBean permGenBean = null;
            for (MemoryPoolMXBean mx : ManagementFactory.getMemoryPoolMXBeans()) { // <=== EXCEPTION
                if (mx.getName() != null && mx.getName().contains("Perm")) {
                    permGenBean = mx;
                    break;
                }
            }
            permGenStats = new MBeanMemoryStats(permGenBean);
        }
    }