How to merge two JsonArray?

All the answers I found for the same question involve org.json.JSONArray. I need a solution for javax.json.JsonArray.

I have two JSON arrays and when I try to merge them with array1.addAll(array2) I get an java.lang.UnsupportedOperationException.

...
JsonObject users = getUsers(searchBase, filter, (String[]) null);
...
final JsonObject guests = getUsers(searchBase, filter, (String[]) null);

users.getJsonArray("Resources").addAll(guests.getJsonArray("Resources"));
...

The JsonObjects (users and guests) I get back have both this form:

{
    "startIndex": 1,
    "totalResults": 7,
    "itemsPerPage": 7,
    "schemas": [
        "urn:ietf:params:scim:api:messages:2.0:ListResponse"
    ],
    "Resources": [
        {
            "attr1": "value1",
            "attr2": "value2",
			"attr3": "value3",
			"attr4": "value4",
        },
        {
            "attr1": "value5",
            "attr2": "value6",
			"attr3": "value7",
			"attr4": "value8",
        },
		...
    ]
}

Why do I get this error?

How do I have to do to merge them then?

EDIT:
The correct answer is the one of tonakai. Unfortunately it is a comment and I cannot set it as the accepted answer.

I guess you are looking for JsonArrayBuilder.

Following code worked for me:

import java.io.*;
import javax.json.*;
public class Test {
public static void main(String[] args) throws FileNotFoundException, IOException {
InputStream fileInputStream = new FileInputStream("ABSOLUTE_PATH_TO_FILE\\jsonData.json");
JsonReader jsonReader = Json.createReader(fileInputStream);
JsonObject jsonObject = jsonReader.readObject();
JsonArrayBuilder users = Json.createArrayBuilder(jsonObject.getJsonArray("Resources"));
JsonArrayBuilder guests = Json.createArrayBuilder(jsonObject.getJsonArray("Resources"));
users.addAll(guests);
System.out.println(users.build());
jsonReader.close();
fileInputStream.close();
}
}

The file that I used here was created based on the JSON you provided in the question:

{
"startIndex":1,
"totalResults":7,
"itemsPerPage":7,
"schemas":[
"urn:ietf:params:scim:api:messages:2.0:ListResponse"
],
"Resources":[
{
"attr1":"value1",
"attr2":"value2",
"attr3":"value3",
"attr4":"value4"
},
{
"attr1":"value5",
"attr2":"value6",
"attr3":"value7",
"attr4":"value8"
}
]
}