使用 Jersey 自动生成 wadl 时 EnumMap 中出现 NullPointerException

Question

我正在使用 Tomcat 7、Jaxb2 和 Jersey1.11。 我有一个类 EnumProperty，它继承自抽象类 Property。

@XmlAccessorType(XmlAccessType.FIELD)
public class EnumProperty extends Property<Enum> {
@XmlElement(name = "property_value", nillable = true)
private Enum value;

    public EnumProperty() {
        setValueType(PropertyValueTypeEnum.ENUM);
    }

    @Override
    public Enum getValue() {
        return value;
    }

    @Override
    public void setValue(Enum value) {
        this.value = value;
    }
}

Property 类还有其他子类。此外，我还有另一个类 Entity，它包含属性的集合。我还有一个资源，它在其子资源之一中返回一个集合。当我尝试生成应用程序 wadl 时，我收到 NullPointerException。我将问题隔离到 EnumProperty 类。谁能帮我理解问题出在哪里？

java.lang.NullPointerException
java.util.EnumMap.<init>(Unknown Source)
com.sun.xml.bind.v2.model.impl.RuntimeEnumLeafInfoImpl.<init>(RuntimeEnumLeafInfoImpl.java:87)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createEnumLeafInfo(RuntimeModelBuilder.java:109)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createEnumLeafInfo(RuntimeModelBuilder.java:85)
com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:228)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:213)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:319)
com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:81)
java.util.AbstractList$Itr.next(Unknown Source)...