You can convert it to a JavaBean if you want using:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
gson.fromJson(jsonString, JavaBean.class)
To use JsonObject, which is more flexible, use the following:
String json = "{\"Success\":true,\"Message\":\"Invalid access token.\"}";
JsonParser jsonParser = new JsonParser();
JsonObject jo = (JsonObject)jsonParser.parse(json);
Assert.assertNotNull(jo);
Assert.assertTrue(jo.get("Success").getAsString());
Which is equivalent to the following:
JsonElement jelem = gson.fromJson(json, JsonElement.class);
JsonObject jobj = jelem.getAsJsonObject();
GitHub
google.github.io › gson › UserGuide.html
Gson User Guide | gson
Gson gson = new Gson(); int[] ints = {1, 2, 3, 4, 5}; String[] strings = {"abc", "def", "ghi"}; // Serialization gson.toJson(ints); // ==> [1,2,3,4,5] gson.toJson(strings); // ==> ["abc", "def", "ghi"] // Deserialization int[] ints2 = gson.fromJson("[1,2,3,4,5]", int[].class); // ==> ints2 will be same as ints ·
Baeldung
baeldung.com › home › json › convert string to jsonobject with gson
Convert String to JsonObject with Gson | Baeldung
May 5, 2025 - In this tutorial, we’ll learn how Gson can give us a JsonObject from a String.
Help with using Gson to convert simple JSON string to Java object
Please ensure that: Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions You include any and all error messages in full You ask clear questions You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions. Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar If any of the above points is not met, your post can and will be removed without further warning. Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://imgur.com/a/fgoFFis ) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc. Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit. Code blocks look like this: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above. If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures. To potential helpers Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com
10
0
July 28, 2022java - Gson: Directly convert String to JsonObject (no POJO) - Stack Overflow
Can't seem to figure this out. I'm attempting JSON tree manipulation in GSON, but I have a case where I do not know or have a POJO to convert a string into, prior to converting to JsonObject. Is th... More on stackoverflow.com
Strings with characters " and \ causing issues when parsing to class using fromJSON
Gson version 2.10 Java / Android version openjdk version "17.0.3" Used tools Maven; version: Apache Maven 3.8.5 Description When using fromJSON to parse JSON into a class with a String me... More on github.com
2
November 25, 2022JSON String to Java object using GSON - Stack Overflow
it help me to convert a json object that have a list inside. I convert the json string to Object.class 2017-01-12T06:28:43.973Z+00:00 ... The reason for the error is that your JSON at the top level is an array, not an object. That is covered by GSON throwing "Expected BEGIN_OBJECT but was ... More on stackoverflow.com
Top answer 1 of 11
195
You can convert it to a JavaBean if you want using:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
gson.fromJson(jsonString, JavaBean.class)
To use JsonObject, which is more flexible, use the following:
String json = "{\"Success\":true,\"Message\":\"Invalid access token.\"}";
JsonParser jsonParser = new JsonParser();
JsonObject jo = (JsonObject)jsonParser.parse(json);
Assert.assertNotNull(jo);
Assert.assertTrue(jo.get("Success").getAsString());
Which is equivalent to the following:
JsonElement jelem = gson.fromJson(json, JsonElement.class);
JsonObject jobj = jelem.getAsJsonObject();
2 of 11
52
To do it in a simpler way, consider below:
JsonObject jsonObject = (new JsonParser()).parse(json).getAsJsonObject();
You can convert it to a JavaBean if you want using:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
gson.fromJson(jsonString, JavaBean.class)
To use JsonObject, which is more flexible, use the following:
String json = "{\"Success\":true,\"Message\":\"Invalid access token.\"}";
JsonParser jsonParser = new JsonParser();
JsonObject jo = (JsonObject)jsonParser.parse(json);
Assert.assertNotNull(jo);
Assert.assertTrue(jo.get("Success").getAsString());
Which is equivalent to the following:
JsonElement jelem = gson.fromJson(json, JsonElement.class);
JsonObject jobj = jelem.getAsJsonObject();
Mkyong
mkyong.com › home › java › convert java objects to from json using gson
Convert Java objects to from JSON using Gson - Mkyong.com
May 6, 2024 - Gson gson = new Gson(); // A Java object Staff obj = new Staff(); // Converts Java object to JSON string String json = gson.toJson(obj); // Converts Java object to File try (Writer writer = new FileWriter("staff.json")) { gson.toJson(staff, writer); } catch (IOException e) { throw new RuntimeException(e); } Converts JSON to Java objects using gson.fromJson().
GitHub
github.com › google › gson
GitHub - google/gson: A Java serialization/deserialization library to convert Java Objects into JSON and back · GitHub
This avoids Gson's runtime crashes when optimizations are applied (usually due to the fields missing or being obfuscated), and results in faster performance on Android devices. The Moshi APIs may be more familiar to users who already know Gson. If you still want to use Gson and attempt to avoid these crashes, you can see how to do so here. Provide simple toJson() and fromJson() methods to convert Java objects to JSON and vice-versa
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Reddit
reddit.com › r/javahelp › help with using gson to convert simple json string to java object
r/javahelp on Reddit: Help with using Gson to convert simple JSON string to Java object
July 28, 2022 -
I'm new to Java but I have experience with Python and Swift so I'm familiar with the concept of creating custom objects to decode json.
I've been at this for hours looking at tons of documentation and tutorial pages and nothing has fixed the issue.
JsonTest.java
package com.joerex.httpjson;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
public class JsonTest {
public static void main(String[] args) {
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
String jsonString = "{'favoriteColor':'blue'}";
// JsonElement jsonElem = JsonParser.parseString(jsonString);
// JsonObject jsonObj = jsonElem.getAsJsonObject();
// code breaks here
var favColor = gson.fromJson(jsonString, FavoriteColor.class);
System.out.println(favColor);
}
}FavoriteColor.java
package com.joerex.httpjson;
public class FavoriteColor {
public String favoriteColor;
}Here's the error message I'm getting -
Exception in thread "main" com.google.gson.JsonIOException: Failed making field 'com.joerex.httpjson.FavoriteColor#favoriteColor' accessible; either change its visibility or write a custom TypeAdapter for its declaring type at com.google.gson@2.9.0/com.google.gson.internal.reflect.ReflectionHelper.makeAccessible(ReflectionHelper.java:22) at com.google.gson@2.9.0/com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:158) at com.google.gson@2.9.0/com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:101) at com.google.gson@2.9.0/com.google.gson.Gson.getAdapter(Gson.java:501) at com.google.gson@2.9.0/com.google.gson.Gson.fromJson(Gson.java:990) at com.google.gson@2.9.0/com.google.gson.Gson.fromJson(Gson.java:956) at com.google.gson@2.9.0/com.google.gson.Gson.fromJson(Gson.java:905) at com.google.gson@2.9.0/com.google.gson.Gson.fromJson(Gson.java:876) at HelloWorld/com.joerex.httpjson.JsonTest.main(JsonTest.java:33) Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field public java.lang.String com.joerex.httpjson.FavoriteColor.favoriteColor accessible: module HelloWorld does not "exports com.joerex.httpjson" to module com.google.gson at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:340) at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:280) at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:176) at java.base/java.lang.reflect.Field.setAccessible(Field.java:170) at com.google.gson@2.9.0/com.google.gson.internal.reflect.ReflectionHelper.makeAccessible(ReflectionHelper.java:19) ... 8 more
EDIT:
SOLVED! The issue was my in my module-info.java file which I did not include in my original post. Needed to open up my module to the Gson module. I still don't completely understand why - cause I thought making a class "public" would be enough
module com.joerex.httpjson {
exports com.joerex.httpjson;
opens com.joerex.httpjson to com.google.gson;
requires com.google.gson;
requires java.net.http;
}
Top answer 1 of 3
1
Please ensure that: Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions You include any and all error messages in full You ask clear questions You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions. Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar If any of the above points is not met, your post can and will be removed without further warning. Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://imgur.com/a/fgoFFis ) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc. Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit. Code blocks look like this: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above. If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures. To potential helpers Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.
2 of 3
1
try adding the setter method for favorite color in the favourite colour class. Not sure if Gson works with public properties. Ohhh, nvm. The error message states that your module is not exported. Can't help you with that, but you should able to google it from here
Crunchify
crunchify.com › json tutorials › how to use gson -> fromjson() to convert the specified json into an object of the specified class
How to use Gson -> fromJson() to convert the specified JSON into an Object of the Specified Class • Crunchify
February 16, 2023 - package crunchify.com.tutorials; ... /** * @author Crunchify.com * Gson() -> fromJson() to deserializes the specified Json into an object of the specified class */ public class CrunchifyGoogleGSONExample { public static void ...
Mkyong
mkyong.com › home › java › how to parse json using gson
How to parse JSON using Gson - Mkyong.com
May 2, 2024 - package com.mkyong.json.gson; import com.google.gson.Gson; import com.mkyong.json.model.Person; public class GsonParseJsonStringExample { public static void main(String[] args) { String json = "{\"name\": \"mkyong\", \"age\": 20}"; Gson gson = new Gson(); Person person = gson.fromJson(json, Person.class); System.out.println(person); } } JSON Array.
ZetCode
zetcode.com › java › gson
Java Gson - JSON serialization and deserialization in Java with Gson
October 10, 2024 - import com.google.gson.Gson; void main() { String json_string = """ {"firstName":"Tom", "lastName": "Broody"}"""; Gson gson = new Gson(); User user = gson.fromJson(json_string, User.class); System.out.println(user); } record User(String firstName, String lastName) { }
HowToDoInJava
howtodoinjava.com › home › gson › gson jsonparser
Gson JsonParser (with Examples) - HowToDoInJava
April 4, 2023 - String json = "{'id': 1001, " + "'firstName': 'Lokesh'," + "'lastName': 'Gupta'," + "'email': 'howtodoinjava@gmail.com'}"; JsonObject jsonObject = new Gson().fromJson(json, JsonObject.class); System.out.println(jsonObject.get("id")); ...
Top answer 1 of 10
567
use JsonParser; for example:
CopyJsonObject o = JsonParser.parseString("{\"a\": \"A\"}").getAsJsonObject();
2 of 10
152
Try to use getAsJsonObject() instead of a straight cast used in the accepted answer:
CopyJsonObject o = new JsonParser().parse("{\"a\": \"A\"}").getAsJsonObject();
GitHub
github.com › google › gson › issues › 2244
Strings with characters " and \ causing issues when parsing to class using fromJSON · Issue #2244 · google/gson
November 25, 2022 - When using fromJSON to parse JSON into a class with a String member and the source JSON string contains " or \, then GSON will either produce wrong string or throw an exception.
Author pjoe
HowToDoInJava
howtodoinjava.com › home › gson › gson tutorial: read and write json with examples
Gson Tutorial: Read and Write JSON with Examples
August 27, 2023 - Getting Started Guide – Learn to use GSON to serialize a simple Java Object into the JSON representation and to deserialize the JSON string to an equivalent Java object.
Java67
java67.com › 2017 › 05 › how-to-convert-json-string-to-java-object-gson-example.html
How to convert JSON String to Java Object using Gson? JSON Deserialization Example | Java67
You can use any JSON library to perform serialization and de-serialization like Jackson Databind, Gson, or Json-simple. In this program, I'll show you how to use Gson to create a Java object from a given JSON String. In order to start with, we need a JSON String.
HowToDoInJava
howtodoinjava.com › home › gson › gson – read and write json
Gson - Read and Write JSON - HowToDoInJava
April 4, 2023 - Deserialization in the context of Gson means converting a JSON string to an equivalent Java object. To do the deserialization, we need a Gson object and call the function fromJson() and pass two parameters i.e. JSON string and expected java ...
Coderanch
coderanch.com › t › 631611 › open-source › GSON-deserialize-JSON-String
Using GSON to deserialize a JSON String (Open Source Projects forum at Coderanch)
There's a LOT of stuff in that post, which leads me to suspect that you're flapping around for a solution. I'm no GSON or JSON expert, but the first thing I would do is to break the problem down. And the first thing is, does: DietSchedule schedule = gson.fromJson(jsonContents, DietSchedule.class); return you anything?
Google Sites
sites.google.com › site › gson › gson-user-guide
Gson User Guide - Sign in - Google Accounts
Documentation page for Google Gson
Adobe Developer
developer.adobe.com › experience-manager › reference-materials › 6-4 › javadoc › com › google › gson › Gson.html
Gson ("The Adobe AEM Quickstart and Web Application.")
This method deserializes the Json ... type. For non-generic objects, use fromJson(Reader, Class) instead. If you have the Json in a String form instead of a Reader, use fromJson(String, Type) instead....
Top answer 1 of 2
35
Gson gson = new Gson();
gson.fromJson(jsonStr,YourClass.class);
very easy.
2 of 2
25
The reason for the error is that your JSON at the top level is an array, not an object. That is covered by GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?.
However, the solution there won't work for your JSON because you have an array of mixed types (an object and an array) rather than an array of a single type of object. For that you're going to have to write a custom deserializer (See The section of the Gson user's guide that covers this) or use Gson's JsonParser class directly and extract the data from the parse tree.
Edit from comments above:
If you're the one creating the JSON, it looks like what you want is an array of BoxSearch objects?
Based on your Java BoxSearch class, you'd need JSON structured like:
[
{
"lat1" : 39.737567,
"lat2" : 32.7801399,
"long1" : -104.98471790000002,
"long2" : -96.80045109999998,
"boxes" : [
{
"lat": {
"b": 38.88368709500021,
"d": 40.620468491667026
},
"long": {
"b": -105.75306170749764,
"d": -104.675854661387
}
}
]
}
]
However, the way you have Boxes class defined won't work for that. (Did you mean to have an array of them?). As-is it would need to look like:
class Boxes {
Box lat;
@SerializedName("long")
Box lon;
}
class Box {
String b;
String d;
}
Now you have an array containing one type of object (BoxSearch) which you could deserialize with:
Type collectionType = new TypeToken<Collection<BoxSearch>>(){}.getType();
Collection<BoxSearch> boxSearchCollection = gson.fromJson(json, collectionType);
If you really don't need an array of these, get rid of the outer array and simply do:
gson.fromJson(json, BoxSearch.class);
Stack Overflow
stackoverflow.com › questions › 55971802 › how-does-gson-fromjsonstring-class-work
java - How does Gson.fromJson(String, Class) work? - Stack Overflow
import com.google.gson.annotations.SerializedName data class UsuariosDTO ( @SerializedName("data") var data: List<Usuarios> ) data class Usuarios( @SerializedName("uid") var uid: String, @SerializedName("name") var name: String, @SerializedName("email") var email: String, @SerializedName("profile_pic") var profilePic: String, @SerializedName("post") var post: Post ) data class Post( @SerializedName("id") var id: Int, @SerializedName("date") var date: String, @SerializedName("pics") var pics: List<String> ) I'm able to use (where dataObteined is of UsuariosDTO type): val json = gson.toJson(dataObtained) And later deserialize the json like this: val offUsuariosDTO = gson.fromJson(json, UsuariosDTO::class.java) After looking everywhere I found out my error was UsuariosDTO.class.