Parse a JSON to object JAVA without Root
[
{
"role": "SiteManager",
"authority":
{
    "authorityType": "USER",
    "fullName": "admin",
    "userName": "admin",
    "firstName": "Administrator",
    "lastName": "",
    "url": "/alfresco/service/api/people/admin"
},
"url": "/alfresco/service/api/sites/test3/memberships/admin"
}
,
{
"role": "SiteConsumer",
"authority":
{
    "authorityType": "GROUP",
    "shortName": "jamalgg",
    "fullName": "GROUP_jamalgg",
    "displayName": "jamalgg",
    "url": "/alfresco/service/api/groups/jamalgg"
},
"url": "/alfresco/service/api/sites/test3/memberships/GROUP_jamalgg"
}
,
{
"role": "SiteManager",
"authority":
{
    "authorityType": "GROUP",
    "shortName": "ALFRESCO_ADMINISTRATORS",
    "fullName": "GROUP_ALFRESCO_ADMINISTRATORS",
    "displayName": "ALFRESCO_ADMINISTRATORS",
    "url": "/alfresco/service/api/groups/ALFRESCO_ADMINISTRATORS"
},
"url": "/alfresco/service/api/sites/test3/memberships/GROUP_ALFRESCO_ADMINISTRATORS"
}
]

List<Memberships > listMemberships;

public class Memberships {
private String role;
private List<Authority> listAuthority ;
private String url;
}
public class Authority {
private String  authorityType;
private String  shortName;
private String  fullName;
private String  displayName;
private String  url;
}

ObjectMapper mapper = new ObjectMapper();
User user = mapper.readValue(new File("c:\user.json"), User.class);

Type targetType = new TypeToken<Collection<Memberships>>() {}.getType();
List<Memberships> list = (List<Memberships>)  new Gson().fromJson(renduJson,targetType);

Type targetType = new TypeToken<Collection<Memberships>>() {}.getType();
List<Memberships> list = (List<Memberships>)new Gson().fromJson(rendu,targetType);