adam bien's blog

Java EE 8 with JSON-P 1.1 ("JavaTM API for JSON Processing", JSR-374) introduced an overloaded Json#createObjectBuilder(JsonObject input) method which uses the JsonObject to set the initial state of the builder.

The pre-initialialization significantly simplifies updates:

import javax.json.Json;
import javax.json.JsonArray;
import javax.json.JsonArrayBuilder;
import javax.json.JsonObject;
//...
            
@Test
public void jsonObjectUpdate() {
    String key = "update";
    String JAVA_EE_8 = "is easy with Java EE 8";

    JsonObject initial = Json.createObjectBuilder().
            add(key, "was hard in Java EE 7").
            build();

    JsonObject updated = Json.createObjectBuilder(initial).
            add(key, JAVA_EE_8).
            build();

    assertThat(updated.getString(key), is(JAVA_EE_8));
    assertThat(updated.size(), is(1));
}