### Question:
Link implements HasJsonKey { @XmlTransient @JsonIgnore public String getHttpHeaderValue() { StringBuilder builder = new StringBuilder("<"); if (this.href != null) { builder.append(this.href.toString()); } builder.append(">"); if (this.rel != null) { builder.append("; rel=\"").append(this.rel).append("\""); } if (this.template != null) { builder.append("; template=\"").append(this.template).append("\""); } if (this.type != null) { builder.append("; type=\"").append(this.type).append("\""); } if (this.accept != null) { builder.append("; accept=\"").append(this.accept).append("\""); } if (this.allow != null) { builder.append("; allow=\"").append(this.allow).append("\""); } if (this.hreflang != null) { builder.append("; hreflang=\"").append(this.hreflang).append("\""); } if (this.title != null) { builder.append("; title=\"").append(this.title).append("\""); } if (this.count != null) { builder.append("; count=\"").append(this.title).append("\""); } if (this.offset != null) { builder.append("; offset=\"").append(this.title).append("\""); } if (this.results != null) { builder.append("; results=\"").append(this.title).append("\""); } return builder.toString(); } Link(String rel, URI href);  Link(); @XmlTransient @JsonIgnore @Override boolean isHasUniqueKey(); @XmlAttribute @JsonIgnore String getRel(); @JsonIgnore void setRel(String rel); Link rel(String rel); @XmlTransient @JsonIgnore @Override String getJsonKey(); @Override @JsonIgnore void setJsonKey(String jsonKey); @XmlAttribute @XmlSchemaType (name = "anyURI", namespace = XMLConstants.W3C_XML_SCHEMA_NS_URI) URI getHref(); void setHref(URI href); Link href(URI href); @XmlAttribute String getTemplate(); void setTemplate(String template); Link template(String template); @XmlAttribute String getType(); void setType(String type); Link type(String type); @XmlAttribute String getAccept(); void setAccept(String accept); Link accept(String accept); @XmlAttribute String getAllow(); void setAllow(String allow); Link allow(String allow); @XmlAttribute String getHreflang(); void setHreflang(String hreflang); Link hreflang(String hreflang); @XmlAttribute String getTitle(); void setTitle(String title); Link title(String title); @XmlAttribute Integer getCount(); void setCount(Integer count); Link count(Integer count); @XmlAttribute Integer getOffset(); void setOffset(Integer offset); Link offset(Integer offset); @XmlAttribute Integer getResults(); void setResults(Integer results); Link results(Integer results); @XmlTransient @JsonIgnore String getHttpHeaderValue(); @Override String toString(); static final Set<String> NON_UNIQUE_RELS; }### Answer:
@Test public void testHeaderValueForUninitializedLink() throws Exception { Link link = new Link(); assertEquals("<>", link.getHttpHeaderValue()); }