Java StackOverflowError error when converting object to JSON

I have the following Java object.

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(
    name = "ApprovalRequest",
    propOrder = {"requiredConclusionTime", "approvalType", "businessRequest", "supportingInfo", "messageToEvaluator", "organisation", "resubmissionOf", "requestedBy", "nominatedEvaluator", "evaluationStrategy"}
)
public class ApprovalRequest implements Serializable {
    private static final long serialVersionUID = 1L;
    @XmlSchemaType(
        name = "dateTime"
    )
    protected XMLGregorianCalendar requiredConclusionTime;
    protected Integer approvalType;
    @XmlElement(
        required = true
    )
    protected Object businessRequest;
    protected List<Object> supportingInfo;
    protected String messageToEvaluator;
    @XmlElement(
        required = true
    )
    @XmlSchemaType(
        name = "anyURI"
    )
    protected String organisation;
    protected String resubmissionOf;
    protected PersonalInfo requestedBy;
    protected EvaluatorNomination nominatedEvaluator;
    protected EvaluationStrategy evaluationStrategy;

    public ApprovalRequest() {
    }

    public XMLGregorianCalendar getRequiredConclusionTime() {
        return this.requiredConclusionTime;
    }

    public void setRequiredConclusionTime(XMLGregorianCalendar value) {
        this.requiredConclusionTime = value;
    }

    public Integer getApprovalType() {
        return this.approvalType;
    }

    public void setApprovalType(Integer value) {
        this.approvalType = value;
    }

    public Object getBusinessRequest() {
        return this.businessRequest;
    }

    public void setBusinessRequest(Object value) {
        this.businessRequest = value;
    }

    public List<Object> getSupportingInfo() {
        if (this.supportingInfo == null) {
            this.supportingInfo = new ArrayList();
        }

        return this.supportingInfo;
    }

    public String getMessageToEvaluator() {
        return this.messageToEvaluator;
    }

    public void setMessageToEvaluator(String value) {
        this.messageToEvaluator = value;
    }

    public String getOrganisation() {
        return this.organisation;
    }

    public void setOrganisation(String value) {
        this.organisation = value;
    }

    public String getResubmissionOf() {
        return this.resubmissionOf;
    }

    public void setResubmissionOf(String value) {
        this.resubmissionOf = value;
    }

    public PersonalInfo getRequestedBy() {
        return this.requestedBy;
    }

    public void setRequestedBy(PersonalInfo value) {
        this.requestedBy = value;
    }

    public EvaluatorNomination getNominatedEvaluator() {
        return this.nominatedEvaluator;
    }

    public void setNominatedEvaluator(EvaluatorNomination value) {
        this.nominatedEvaluator = value;
    }

    public EvaluationStrategy getEvaluationStrategy() {
        return this.evaluationStrategy;
    }

    public void setEvaluationStrategy(EvaluationStrategy value) {
        this.evaluationStrategy = value;
    }
}

When I do the following:

ApprovalRequest approvalRequest = new ApprovalRequest();
Gson gson = new Gson();
String approvalRequestJsonStr = gson.toJson(approvalRequest);

It works perfectly.

However, when I let the application run on the JBoss server, and at runtime with a populated ApprovalRequest, there's an exception converting the object to JSON.

Gson gson = new Gson();
String approvalRequestJsonStr = gson.toJson(approvalRequest);

Gets the following error:

Caused by: java.lang.StackOverflowError
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.stream.JsonWriter.peek(JsonWriter.java:350)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.stream.JsonWriter.beforeName(JsonWriter.java:565)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.stream.JsonWriter.writeDeferredName(JsonWriter.java:386)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.stream.JsonWriter.value(JsonWriter.java:402)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.TypeAdapters$13.write(TypeAdapters.java:353)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.TypeAdapters$13.write(TypeAdapters.java:337)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
18:40:26,836 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.ObjectTypeAdapter.write(ObjectTypeAdapter.java:105)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
18:40:26,837 ERROR [stderr] (http--0.0.0.0-8443-1)  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
...

Any ideas how I can fix this?