在编写测试时，我实际上发现了您的问题:-)

While writing a test I actually found your problem :-)

import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.IMap;
import com.hazelcast.query.EntryObject;
import com.hazelcast.query.PredicateBuilder;

import java.io.Serializable;
import java.sql.Date;

public class Test
{
    public static void main(String[] args)
    {
        HazelcastInstance hz = Hazelcast.newHazelcastInstance();

        IMap<MyObject, MyEnum> map = hz.getMap("test");

        EntryObject entryObject = new PredicateBuilder().getEntryObject();
        PredicateBuilder builder = entryObject.key().get("date").isNull();

        map.addIndex("__key#date", true);

        map.put(new MyObject(), MyEnum.TEST_ENUM);
    }

    public static class MyObject implements Serializable
    {
        private Date date;

        public Date getDate()
        {
            return date;
        }

        public void setDate(Date date)
        {
            this.date = date;
        }
    }

    public static enum MyEnum {
        TEST_ENUM;
    }
}

诀窍是基于map键而不是默认值创建索引.您已经在查询entryObject.key()中进行了此操作，但是在索引定义__key.date中未进行此操作.

The trick is to create the index based on the map-key and not the value which is taken by default. You already did it in your query entryObject.key() but missed it on the index definition __key.date.