1# Gson 2 3Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. 4Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. 5 6There are a few open-source projects that can convert Java objects to JSON. However, most of them require that you place Java annotations in your classes; something that you can not do if you do not have access to the source-code. Most also do not fully support the use of Java Generics. Gson considers both of these as very important design goals. 7 8:information_source: Gson is currently in maintenance mode; existing bugs will be fixed, but large new features will likely not be added. If you want to add a new feature, please first search for existing GitHub issues, or create a new one to discuss the feature and get feedback. 9 10### Goals 11 * Provide simple `toJson()` and `fromJson()` methods to convert Java objects to JSON and vice-versa 12 * Allow pre-existing unmodifiable objects to be converted to and from JSON 13 * Extensive support of Java Generics 14 * Allow custom representations for objects 15 * Support arbitrarily complex objects (with deep inheritance hierarchies and extensive use of generic types) 16 17### Download 18 19Gradle: 20```gradle 21dependencies { 22 implementation 'com.google.code.gson:gson:2.10' 23} 24``` 25 26Maven: 27```xml 28<dependency> 29 <groupId>com.google.code.gson</groupId> 30 <artifactId>gson</artifactId> 31 <version>2.10</version> 32</dependency> 33``` 34 35[Gson jar downloads](https://maven-badges.herokuapp.com/maven-central/com.google.code.gson/gson) are available from Maven Central. 36 37 38 39### Requirements 40#### Minimum Java version 41- Gson 2.9.0 and newer: Java 7 42- Gson 2.8.9 and older: Java 6 43 44Despite supporting older Java versions, Gson also provides a JPMS module descriptor (module name `com.google.gson`) for users of Java 9 or newer. 45 46#### JPMS dependencies (Java 9+) 47These are the optional Java Platform Module System (JPMS) JDK modules which Gson depends on. 48This only applies when running Java 9 or newer. 49 50- `java.sql` (optional since Gson 2.8.9) 51When this module is present, Gson provides default adapters for some SQL date and time classes. 52 53- `jdk.unsupported`, respectively class `sun.misc.Unsafe` (optional) 54When this module is present, Gson can use the `Unsafe` class to create instances of classes without no-args constructor. 55However, care should be taken when relying on this. `Unsafe` is not available in all environments and its usage has some pitfalls, 56see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()). 57 58### Documentation 59 * [API Javadoc](https://www.javadoc.io/doc/com.google.code.gson/gson): Documentation for the current release 60 * [User guide](https://github.com/google/gson/blob/master/UserGuide.md): This guide contains examples on how to use Gson in your code. 61 * [Change log](https://github.com/google/gson/blob/master/CHANGELOG.md): Changes in the recent versions 62 * [Design document](https://github.com/google/gson/blob/master/GsonDesignDocument.md): This document discusses issues we faced while designing Gson. It also includes a comparison of Gson with other Java libraries that can be used for Json conversion 63 64Please use the ['gson' tag on StackOverflow](https://stackoverflow.com/questions/tagged/gson) or the [google-gson Google group](https://groups.google.com/group/google-gson) to discuss Gson or to post questions. 65 66### Related Content Created by Third Parties 67 * [Gson Tutorial](https://www.studytrails.com/java/json/java-google-json-introduction/) by `StudyTrails` 68 * [Gson Tutorial Series](https://futurestud.io/tutorials/gson-getting-started-with-java-json-serialization-deserialization) by `Future Studio` 69 * [Gson API Report](https://abi-laboratory.pro/java/tracker/timeline/gson/) 70 71### License 72 73Gson is released under the [Apache 2.0 license](LICENSE). 74 75``` 76Copyright 2008 Google Inc. 77 78Licensed under the Apache License, Version 2.0 (the "License"); 79you may not use this file except in compliance with the License. 80You may obtain a copy of the License at 81 82 http://www.apache.org/licenses/LICENSE-2.0 83 84Unless required by applicable law or agreed to in writing, software 85distributed under the License is distributed on an "AS IS" BASIS, 86WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 87See the License for the specific language governing permissions and 88limitations under the License. 89``` 90 91### Disclaimer 92 93This is not an officially supported Google product. 94
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