Convert Pojo To Json Using Gson

You can use Google's GSON parser. Pretty print JSON 4. Some points to be considered when using Gson: If the JSON string holds an invalid object attribute, then Gson implicitly ignores it. {"widget": { "debug": "on", "window": { "title": "Sample Konfabulator Widget", "name": "main_window", "width": 500, "height": 500 }, "image": { "src": "Images/Sun. Unlike the once popular XML, JSON. The Google’s GSON library is purely awesome. Java example to convert JSON to Java Object. x used for data-binding. Our first goal is to get all the cryptocurrencies list using Retrofit from the Internet. We are going to use the fromJson method of the Gson library to convert a JSON string to a Java object. gson gson 1. x to convert Java object to/from JSON using Jackson API. Mapping JSON to Java objects (and vice versa) is from the 90s. Fetch json data Using GSON Library in Android GSON Library is a powerful Library developed by Google which is used to Quick parse the JSON into JSON Objects. There are no ads, popups or nonsense, just a JSON string extractor. Read simple JSON String You can use fromJson(String json, Class classOfT) method to read simple Json string. Convert the JSON to Person[] array. java, we will create employee list and convert it into JSON. I found that many of the tutorials on the net and here on SO also refer to net. A big reason that GSON is such a popular library is how simple it makes both processes. We will use the Google gson library to serialize POJO to JSON and deserialize JSON to POJO. This video shows 1. The method accepts two parameters: the JSON string, and the Class object that represents the JSON string. json library to convert an xml file to json object. As per definition of POJO (Plain Old Java Object) is the class with out any restriction, having getter and setter methods, if required can also implement object class methods like equals(), toString() etc. ObjectMapper Use objectMapper. JSON can represent two structured types: objects and arrays. REST Web Services use it. The Android SDK includes a set of classes for reading and writing JSON-based text, but they’re a bit cumbersome. Google Gson - Java json processor. Mock a simple Json String. So you can define your POJO and provide some annotations to generate XML from a Java object. Sample Json String Gson gson = new. toJson(obj); Pick your library and go. Creating a POJO class based on JSON is time-consuming and error-prone. EDITS: Calling toString on Date is for illustrative purposes. Your plugin for one of our team tools might be of great use to millions of users. a some parts of it don’t adhere to a specific pre-defined schema. On Medium, smart voices and. (Just download the jar and drag it into your libs folder) Create the POJO; Serialize the POJO into a JSON String using GSON. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. Gson is a Java library that can be used to convert Java Objects into their JSON representation. Java POJO to JSON using com. How to Read and Write JSON data in Kotlin with GSON. Parsing JSON using GSON within a Maven project in IntelliJ IDEA. If you want to use data flexibly, we need to convert the JSON string into an object. how to convert a Java POJO to JSON string? String json = gson. This tutorial focuses on the JsonParser though - GSON's tree parser. See details here. It can also be used to convert a JSON string to an equivalent Java object. Is there a way to go directly from a String to JsonObject? I've tried the following (Scala syntax): val gson. below is the working code. fromJson(jsonResponse, Obj. It is commonly used for transmitting data in web applications. How to Parse JSON to/from Java Object using Boon JSON Parser; How to Read and Write JSON using GSON; How to write JSON object to File in Java? How to read JSON file in Java - JSONObject and JSONArray; Jersey Jackson JSON Tutorial; Spring REST Hello World Example - JSON and XML responses; How to Convert Java Object to JSON using JAXB; JAX-RS. In Gson (and most JSON parsers), the following mappings exist: a JSON string maps to a Java String; a JSON number maps to a Java Number type; a JSON array maps to a Collection type or an array type; a JSON object maps to a Java Map type or, typically, a custom POJO type (not mentioned previously); null maps to Java's null, and the boolean. This video shows 1. The Google's Gson library provides a class with the same name (Gson) which is the main class of the library. Note: Refer How to convert java object to json string using Gson APIs? page for dependent libraries. loginController; import java. Associated with a tool like JsonSchema2Pojo, it becomes a pleasure to use JSON data in Java. Once you converted Java objects to JSON you can now pass it thru intent bundle as a String. {"widget": { "debug": "on", "window": { "title": "Sample Konfabulator Widget", "name": "main_window", "width": 500, "height": 500 }, "image": { "src": "Images/Sun. In server-side, I'll use GSON to convert from POJO to JSON, as I think. Analyze your JSON string as you type with an online Javascript parser, featuring tree view and syntax highlighting. Load JSON, get a string. This library is awesome and very useful, but you need a good architecture and a good practice to use it as best as possible. Make any JSON format a hypermedia format with no constraints on document structure; Allows use of URI Templates with instance data; Describe client data for use with links using JSON Schema. Here, we're going to use Gson only to parse JSON content. GSON can work with arbitrary Java objects including pre existing objects that you do not have source-code of. Convert the JSON to List of. Before jumping into code examples, lets define a simple pojo class which we will use in this example for conversion purpose. Both POJO classes are copied from How to convert object to / from JSON using Gson tutorial. In this article, I would like to suggest a few online websites to auto-generate Java POJO class from JSON. In order to convert JSON to a List, we use new TypeToken, which indicates the type that we want Gson to return. fromJson(jsonData, Vehicles. Goals for Gson Provide easy to use mechanisms like toString() and constructor (factory method) to convert Java to JSON and vice-versa •. Get Started With Retrofit 2 HTTP Client and also Google's Gson library to convert JSON to POJO The screenshot below is the JSON response using Postman. stands for YAML ain't markup language and is a superset of JSON - Convert YAML to JSON. Your plugin for one of our team tools might be of great use to millions of users. With a few lines of code, you can pass JSON and get fully-mapped Java objects back. So though I love how easy it is for me to type: Gson gson = new Gson(); gson. Mapping JSON to Java objects (and vice versa) is from the 90s. Goals for Gson Provide easy to use mechanisms like toString() and constructor (factory method) to convert Java to JSON and vice-versa •. toJson(Object src) or vice-versa. Annotate POJO members with @SerializedName annotation with desired property name. Data Driven Testing using Json with Cucumber, How to read Json using Gson, How to convert JSOn in to Java POJO object. In cars_object_json. So if you have a key in your JSON with an underscore, for example image_url, you will get setters and getters with underscores: getImage_url() and setImage_url(). Converting BSON Type ObjectId to JSON (Storing in Mongodb) -Java. How to convert JSON to JAVA Objects i. Copy and paste Json to TestEditor displayed in link. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. These JSON structures are represented as object models using the Java types JsonObject and JsonArray. Maven Dependency: com. First of all, create a local instance of gson using the below code. See details here. Once we get the data using Android Volley's Library - we will parse that json response using Google's GSON library. Capturing JSON Object data using Retrofit Android. I want to modify a json content without converting it into a POJO. Examples Listing 1) Two ways to create Gson objects 2) Convert Java objects to JSON format 3) Convert JSON to Java Objects 4) Writing an Instance Creator 5) Custom Serialization and De-serialization 6) Pretty Printing for JSON Output Format 7) Versioning Support. I have bought one android application template from codecanyon. How to deserialize JSon to Java class. We will get back a JSON data result and then convert it using the Gson library. java, one for Grabbing Array data and other for Object data. Importing GSON :. It requires only one jar and is very simple to use: Converting a java object into a JSON string:. HTTP Request with Fuel. Here is a simple example of converting objects into JSON strings and back using Gson. Convert Java object to JSON 3. JSON or JavaScript Object Notation is a language-independent open data format that uses human-readable text to express data objects consisting of attribute-value pairs. Class Declaration. 创建一个包含变量的java类,其名称和数据类型与JSON对象的键相同。. Create an Android app. How to Parse JSON to/from Java Object using Boon JSON Parser; How to Read and Write JSON using GSON; How to write JSON object to File in Java? How to read JSON file in Java - JSONObject and JSONArray; Jersey Jackson JSON Tutorial; Spring REST Hello World Example - JSON and XML responses; How to Convert Java Object to JSON using JAXB; JAX-RS. HTTP Request with Fuel. It is of two types. CSVJSON format variant is not valid CSV however every value is valid JSON. I'm using Jackson JSON library to convert some JSON objects to POJO classes on an android application. 1 Convert a JSON Array to a List. Convert JSON to Java Object. 3 will let you find a way to set the POJO id attribute after saving; right now it's done for free, but not perfectly). Makes the code shorter and cleaner. Thus converting the ArrayList to single singular elements. The use the resulting ArrayList of Pojos for business logic and presentation (Primefaces) Also convert the resulting ArrayList of Pojo's to JSON array of objects, but remove Pojo properties in the conversions that is not needed in the web-client; Push the converted JSON to the web-client for presentation. The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. There are no ads, popups or nonsense, just a JSON string extractor. The Jackson JsonGenerator is used to generate JSON from Java objects (or whatever data structure your code generates JSON from). A quick look at how to convert a POJO from/to a Map I have a nested map and all I want are the fields and values so I quickly thought:. You can unmarshal JSON String to Object or JSON file to Object, both. Convert Java object to JSON using GSON. Here is a simple example of converting objects into JSON strings and back using Gson. How to convert a String to long in Java. Mock a simple Json String. How to convert json string to java object using Gson APIs? This page shows how to convert json string to java object using Google gson API. Typically it involves only two steps, Create instance of com. It builds a tree of JsonElements. Map, since this appears to be the only way to deserialize arbitrary JSON when using Gson. Converting JSON to XML. Convert Json object to Java and Java object. Here's an example on how you can convert json to java object. Data Driven Testing using Json with Cucumber, How to read Json using Gson, How to convert JSOn in to Java POJO object. Convert the JSON to Person[] array. We will use the Google gson library to achieve the conversion. Convert JSON to List in Java. Be aware that it might have changed now that you are access this tutorial. Flexible and has awesome inbuilt plugins. Gson is a Java library that can be used to convert Java Objects into their JSON representation. com using this link you can create a pojo class of response. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. Gson is a Java library capable of converting Java objects into their JSON representation and JSON strings to an equivalent Java object without the need for placing Java annotations in your classes. This is the code I am using this for (in order for it to compile properly, both classes of java code need to be compiling at the same time: Most importantly is my code for testing the JSON conversion method:. There are some other java libraries also capable of doing this conversion, but Gson stands among very few which does not require. OK) public @ResponseBody ConsignmentTrackData updateConsignment(@RequestBody(required=false) ConsignmentTrackData json). Welcome back to another blog post in our Gson series. The Jackson JsonNode class is the Jackson tree object model for JSON. Project Structure. Check out Convert Java Object to JSON using GSON Order POJO Class - object to be serialized and deserialized Let's first define an object to be serialized and deserialized - Order. Given the user defined object or POJO, having Date field, we would like to serialize the POJO to JSON. | up vote 0 down vote I discovered my self that deserialize Documents to POJO with GSON will not work for the _id without some modifications. fromJson(jsonString, Player. JAXB Dependency. Follow below link to see more JSON issues solutions: JSON Issues. Online tool to convert your CSV or TSV formatted data to JSON. simpleSimple Java library for JSON, to read and write […]. How to convert java object to json string using Gson APIs? This page shows how to convert java object to JSON string using Google gson API. Using Gson is a great way to simplify Serialization and Deserialization code by using POJO objects. It's implemented by passing a custom JsonReader (that wraps XmlPullParsers ) to Gson. gson gson 1. My POST request has a body which is complex JSON like this:. Make sure to select JSON as the Source Type: Set the Annotation style to Gson. 3 will let you find a way to set the POJO id attribute after saving; right now it's done for free, but not perfectly). The @JsonAdapter annotation is one of userful GSON annotations. json2csharp is joining forces with quicktype to offer new and improved features including JSON attributes, PascalCase properties, modern C# syntax (nullables, expression members), Dictionary detection, class deduplication, and more. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. GSON is Google's JSON parser and generator for Java. Goals for Gson. [英] Parsing JSON to Java POJO's using GSON. This annotation be used at field or class level to specify the Gson TypeAdapter for serializing or deserializing. YAML vs JSON. How I can define a POJO with collection of object and map corresponding field for above JSON string. How to Read JSON Object From File in Java – Crunchify Tutorial Last Updated on July 17th, 2017 by App Shah 40 comments In this Java Example I’ll use the same file which we have generated in previous tutorial. (Just download the jar and drag it into your libs folder) Create the POJO; Serialize the POJO into a JSON String using GSON. Conversion of POJO to JSON and JSON to POJO In the previous post I explained that how to convert POJO to XML and XML to POJO? How to use GSON API; How to create. In this example program, we are showing simple program about, How to Convert JSON to List in Java. Using Jackson, you can easily handle automatic conversion from Java objects to JSON and back. You can see many Java applications started to throw away XML format and start using json as a new s data-interchange format. Json stands for JavaScript Object Notation. Previously on this endpoint I was using Gson to do the conversion. Converting POJO to Map and vice versa with Jackson. Let's get going. Make any JSON format a hypermedia format with no constraints on document structure; Allows use of URI Templates with instance data; Describe client data for use with links using JSON Schema. Be aware that it might have changed now that you are access this tutorial. Class Declaration. xml file for your reference:. GSON provides two useful methods and everything moven around these two methods. A big reason that GSON is such a popular library is how simple it makes both processes. Gson is an opensource library developed by Google. Once I get the list of documents from database, I’m using the following code to convert it into my Pojo using the following code, for (Document d : documents) { System. Associated with a tool like JsonSchema2Pojo, it becomes a pleasure to use JSON data in Java. I'm using Jackson JSON library to convert some JSON objects to POJO classes on an android application. There are no ads, popups or nonsense, just a JSON string extractor. I am using gson to convert json to model and vice-versa. Quick setup for Retrofit 2 just to try it first. You definitely missing those POJO classes in Flutter. This far, it will deserialize them into my List but each Metric ob. Gson is the main class used for converting JSON to/from java objects. Instant GSON starts with an introduction to the JSON data format. How to deserialize Json with the Gson library - a cookbook with the most common scenarios. Read simple JSON String You can use fromJson(String json, Class classOfT) method to read simple Json string. Data binding API converts JSON to and from POJO using property accessors. Here I'm going to share most useful concept which belongs to the conversion between JavaObjects to JsonObject and JsonObject to JavaObject and JavaObject can be anything like Map or Pojo or something else and sometimes there can be needed to view data stored in a map but if that map is containing big data then there can be difficult to view all data inside that here I will give you most simple. If using a template engine, remember proper escaping of the substituted variables! You will also need a JSON library. In this post, we’ll create a small web application and explore how to return a JSON response from a Java Servlet. GSON should allow you to configure customs (un)marshaller for a given class. We will use GSON, a JSON parsing library developed by Google, to quickly parse the JSON into Java objects with very minimal work required. It provides functionalities to convert Java objects to matching JSON constructs and vice versa. The next answers talk about deserializing JSON to java. 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. Created by developers for developers. For this tutorials, I will use 2 POJO classes: User and Permission and one class as the test. Type or paste a JSON string into the text area above, then click the Generate button to get your result. fromJson(jsonResponse, Obj. It is now used by a number of public projects and companies. As an FYI to anyone starting out with just JSON - from an API they're consuming say: There are a lot of services - utilities and online - which can take the JSON and generate the corresponding class or nested classes automatically. Manually converting from JSON to Java class is heavy task and time consuming so you can use these tools do your job quicker. JSON Stand for JavaScript Object Notation. You can use the GSON TypeToken class to find the generic type for a class. Google json provides methods to convert a JSON string to a Java object. NET stack, Json. Select Source type to Json. File; import org. That's why using AutoValue-Gson to generate CustomTypeAdapter will avoid this reflection cost while staying very simple to update when an api change is happening. In this blog post I will share with you code examples which will help you do most of the tasks you will even need to do when working with JSON and…. This post explains converting Java object to/from JSON using Google GSON library. I'm pretty sure you are able to find many JSON libraries using a simple Google search. 2) Set up options: parse numbers, transpose your data, or output an object instead of an array. We will be requiring the below jars to be put in the classpath for performing the marshalling operation. When marshalling a POJO to JSON you might want to exclude certain fields from the JSON output. A big reason that GSON is such a popular library is how simple it makes both processes. You can’t use JSON Object for that you can convert JSON array into CSV file. Instant GSON is a practical, hands-on guide that provides you with all the implementation features of the GSON API through coded examples, which will help you take advantage of the real power that is behind the GSON API, and give you a good grounding to use it in your projects. Quick setup for Retrofit 2 just to try it first. The JSONObject utility class has a constructor that accepts a Plain Old Java Object and to convert JSON<->XML via JSON<-> Pojo Jackson Vs. GSON is open source and standalone library which is used to convert JSON data into java objects and vice versa. At the bottom of the page click the preview button, this will generate the classes. It is light wight interchange format used over network communication between client and server. At the opposite, it can be used to convert JSON string to Java objects. Rate this: and gson. GSON is simple and easy to use Open-source API to convert JSON formatted data to JAVA Objects and JAVA Object to JSON Representation. How to rename JSON properties (@SerializedName) using Gson APIs? This page shows how to rename json properties when using Gson APIs. Gson is a Java library that can be used to convert Java Objects into their JSON representation. It's super simple to setup and even easier to use: final Gson gson = new GsonBuilder(). View Replies Similar Messages: Read And Write Json To / From A File; Convert JSON String To HashMap In Java; Login Form In 3 Tire Arch Using Swing With Pojo. Firstly, let's see a POJO class which will be converted to JSON for all our examples. That's all about how to parse JSON String in Java and convert a Java object to JSON using Boon. Therefore, to convert a Java object to a JSON String using Jackson. Class Declaration. I've never worked with JSON and I wonder's suggestion that I use to work with the form of JSON that facilitates my work. It can also be used to convert a JSON string to an equivalent Java object. I was tasked with removing the JSON deserialization step from Jersey and into our own module. Importing GSON :. jar 2)code to conver the ResultSet object information to JSON. jsonschema2pojo example,convert json to pojo in java using jackson,json to pojo java code,maven plugin to generate java classes from json schema,json schema to pojo online converter,json to pojo gson,json to object online,tutorial,ai1tutorial. Here is a simple example of converting objects into JSON strings and back using Gson. GSON使用POJO类将JSON解析为java对象。 Create A java class containing variables with names and datatype same as keys of JSON object. Can't seem to figure this out. GSON to the rescue! GSON is a beautiful Java utility library that allows converting to and from JSON and POJOs. How to deserialize Json with the Gson library - a cookbook with the most. I've seen projects with thousands of POJO classes that all existed just so Hibernate could create them, and the only thing they were used for was to generate JSON. Using the Gson library, how do I convert a JSON string to an ArrayList of a custom class JsonLog? Basically, JsonLog is an interface implemented by different kinds of logs made by my Android app--SMS logs, call logs, data logs--and this ArrayList is a collection of all of them. It can also be used to convert a JSON string to an equivalent Java object. I use Google gson library to build a JSON object hierarchy. Conversion of POJO to JSON and JSON to POJO In the previous post I explained that how to convert POJO to XML and XML to POJO? How to use GSON API; How to create. Convert List of Person objects to JSON. writeValue() method. I would recommend you to check how to parse json in android if you have no prior knowledge in parsing json. Gson Map to JSon and JSON to Map Gson can serialize an arbitrary map. Once I get the list of documents from database, I’m using the following code to convert it into my Pojo using the following code, for (Document d : documents) { System. Gson uses the name to match the json property to the java field. Json method helps for converting values to Json and also helps for converting Json to values. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of. After making a GET request to a REST service the natural progression is to POST information back to the server. Before coming to examples, let’s have a POJO class which we will use in given. Converting JSON to XML to Java Objects using XStream Pizza problem- builder vs decorator Adding my Spring MVC hibernate app to OpenShift Implement single click deployment using Jenkins and DeployIt Use ENUM and map to remove conditional logic in your code. The side effect is that reflection is costly performance wise. how to convert a Java POJO to JSON string? String json = gson. How to Parse JSON to/from Java Object using Boon JSON Parser; How to Read and Write JSON using GSON; How to write JSON object to File in Java? How to read JSON file in Java - JSONObject and JSONArray; Jersey Jackson JSON Tutorial; Spring REST Hello World Example - JSON and XML responses; How to Convert Java Object to JSON using JAXB; JAX-RS. Download and add the jar file as dependency for your project. Google developed GSON for internal use but open sourced it later. Convert JSON to Java object. To use Gson or Jackson library, we need to create POJO (Plain Old Java Object) with the same JSON structure. We are going to use Gson in this tutorial but note that there are many other converterFactory you can use like Jackson. simpleSimple Java library for JSON, to read and write […]. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source code of. registerTypeAdapter. I have attached an image to give you a better idea of what I am talking about: I want GSON to create a list of NestedObject1 which will it self contain a list of NestedObject2. Which is a JSON array, now first we need to parse/serialize the JSON to java objects with the classes that represent the data. This tutorial introduces about JSON Annotations via Jackson JSON Annotation Example. Convert the JSON to List of. json file with Java Objects converted to JSON format. Therefore, to convert a Java object to a JSON String using Jackson. In this tutorial, we will show you how to use Jackson 2. For Maven users add the Gson dependency in your pom. It can also be used to convert a JSON string to an equivalent Java object. 1)firs set the class path to gson-2. Gson provides options to print JSON in well-defined way. In this tutorial, we will show you how to use Gson to convert Java object to / from JSON. In this video, we'll Convert JSON into POJO/Model Class Objects using Gson Library. toJson("Hello World"); and easily retrtieve my Json. It works also in reverse order deserializing the specified JSONObject or JSONArray into an object of the specified class. My POST request has a body which is complex JSON like this:. Gson Map to JSon and JSON to Map Gson can serialize an arbitrary map. Google json provides methods to convert a JSON string to a Java object. I am the Gson because I thought that would be the most practical way to convert JSON to POJO and POJO to JSON. Gson is a Java library that can be used to convert Java Objects into their JSON representation. json car_models is an array since there are more than one items in it. Note: Refer How to convert java object to json string using Gson APIs? page for dependent libraries. But, if you found any problem using a class having no no-args constructor, you can useInstanceCreator support. Instant GSON starts with an introduction to the JSON data format. Gson Json Annotations Example, explaining frequently used Google JSON annotations in detail. In my previous article, we looked at reading and writing JSON to a file using JSON. Be aware that it might have changed now that you are access this tutorial. Copy the converted JAVA code and make it work for you. I like to recommend my own Java5 JSON library svenson which has some features that jackson and gson lack. Once I get the list of documents from database, I’m using the following code to convert it into my Pojo using the following code, for (Document d : documents) { System. Learning how to convert Java objects into JSON and JSON into Java will help you a lot in your work as a full stack mobile app developer. Although originally derived from the JavaScript scripting language, JSON data can be generated and parsed with a wide variety of programming languages including JavaScript, PHP. JSON is highly recommended to transmit data between a server and web application. Gson is a Java library that can be used to convert Java Objects into their JSON representation. Get Started With Retrofit 2 HTTP Client and also Google's Gson library to convert JSON to POJO The screenshot below is the JSON response using Postman. Gson example to read a JSON from a file and convert it back to a Java object. Convert a POJO to a JsonObject (GSON 2. json you can see that car_models is an object because there is only one item inside it whereas in cars_array_json. The number of codes will be lessen. There are some other java libraries also capable of doing this conversion, but Gson stands among very few which does not require. how to convert a Java POJO to JSON string? String json = gson. 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. Contribute to abdulwaheed18/JSON-Tutorial development by creating an account on GitHub. addConverterFactory does not convert POJO to. It requires only one jar and is very simple to use: Converting a java object into a JSON string:. if u re using Activity put it onCreate. Goals for Gson Provide easy to use mechanisms like toString() and constructor (factory method) to convert Java to JSON and vice-versa •. In my previous post here, I gave a brief overview of JavaScript Object Notation (JSON). Use this tool to convert JSON into XML format. If the JSON string misses some object attributes, then only the attributes included in the JSON are converted, other attributes take their default values. We will use the Google gson library to achieve serialization and deserialization process. Type or paste a JSON string into the text area above, then click the Generate button to get your result. Nowadays, JSON is the most widespread format to exchange data on the Web. To use this plugin you firstly need to create seperate package like "data", right click the package and you will see Generate POJO from JSON. Creating a JsonParser. Gson example to read a JSON from a file and convert it back to a Java object. In our case, we want an ArrayList, so it's set to new TypeToken(){}. The fact-checkers, whose work is more and more important for those who prefer facts over lies, police the line between fact and falsehood on a day-to-day basis, and do a great job. Today, my small contribution is to pass along a very good overview that reflects on one of Trump’s favorite overarching falsehoods. Namely: Trump describes an America in which everything was going down the tubes under  Obama, which is why we needed Trump to make America great again. And he claims that this project has come to fruition, with America setting records for prosperity under his leadership and guidance. “Obama bad; Trump good” is pretty much his analysis in all areas and measurement of U.S. activity, especially economically. Even if this were true, it would reflect poorly on Trump’s character, but it has the added problem of being false, a big lie made up of many small ones. Personally, I don’t assume that all economic measurements directly reflect the leadership of whoever occupies the Oval Office, nor am I smart enough to figure out what causes what in the economy. But the idea that presidents get the credit or the blame for the economy during their tenure is a political fact of life. Trump, in his adorable, immodest mendacity, not only claims credit for everything good that happens in the economy, but tells people, literally and specifically, that they have to vote for him even if they hate him, because without his guidance, their 401(k) accounts “will go down the tubes.” That would be offensive even if it were true, but it is utterly false. The stock market has been on a 10-year run of steady gains that began in 2009, the year Barack Obama was inaugurated. But why would anyone care about that? It’s only an unarguable, stubborn fact. Still, speaking of facts, there are so many measurements and indicators of how the economy is doing, that those not committed to an honest investigation can find evidence for whatever they want to believe. Trump and his most committed followers want to believe that everything was terrible under Barack Obama and great under Trump. That’s baloney. Anyone who believes that believes something false. And a series of charts and graphs published Monday in the Washington Post and explained by Economics Correspondent Heather Long provides the data that tells the tale. The details are complicated. Click through to the link above and you’ll learn much. But the overview is pretty simply this: The U.S. economy had a major meltdown in the last year of the George W. Bush presidency. Again, I’m not smart enough to know how much of this was Bush’s “fault.” But he had been in office for six years when the trouble started. So, if it’s ever reasonable to hold a president accountable for the performance of the economy, the timeline is bad for Bush. GDP growth went negative. Job growth fell sharply and then went negative. Median household income shrank. The Dow Jones Industrial Average dropped by more than 5,000 points! U.S. manufacturing output plunged, as did average home values, as did average hourly wages, as did measures of consumer confidence and most other indicators of economic health. (Backup for that is contained in the Post piece I linked to above.) Barack Obama inherited that mess of falling numbers, which continued during his first year in office, 2009, as he put in place policies designed to turn it around. By 2010, Obama’s second year, pretty much all of the negative numbers had turned positive. By the time Obama was up for reelection in 2012, all of them were headed in the right direction, which is certainly among the reasons voters gave him a second term by a solid (not landslide) margin. Basically, all of those good numbers continued throughout the second Obama term. The U.S. GDP, probably the single best measure of how the economy is doing, grew by 2.9 percent in 2015, which was Obama’s seventh year in office and was the best GDP growth number since before the crash of the late Bush years. GDP growth slowed to 1.6 percent in 2016, which may have been among the indicators that supported Trump’s campaign-year argument that everything was going to hell and only he could fix it. During the first year of Trump, GDP growth grew to 2.4 percent, which is decent but not great and anyway, a reasonable person would acknowledge that — to the degree that economic performance is to the credit or blame of the president — the performance in the first year of a new president is a mixture of the old and new policies. In Trump’s second year, 2018, the GDP grew 2.9 percent, equaling Obama’s best year, and so far in 2019, the growth rate has fallen to 2.1 percent, a mediocre number and a decline for which Trump presumably accepts no responsibility and blames either Nancy Pelosi, Ilhan Omar or, if he can swing it, Barack Obama. I suppose it’s natural for a president to want to take credit for everything good that happens on his (or someday her) watch, but not the blame for anything bad. Trump is more blatant about this than most. If we judge by his bad but remarkably steady approval ratings (today, according to the average maintained by 538.com, it’s 41.9 approval/ 53.7 disapproval) the pretty-good economy is not winning him new supporters, nor is his constant exaggeration of his accomplishments costing him many old ones). I already offered it above, but the full Washington Post workup of these numbers, and commentary/explanation by economics correspondent Heather Long, are here. On a related matter, if you care about what used to be called fiscal conservatism, which is the belief that federal debt and deficit matter, here’s a New York Times analysis, based on Congressional Budget Office data, suggesting that the annual budget deficit (that’s the amount the government borrows every year reflecting that amount by which federal spending exceeds revenues) which fell steadily during the Obama years, from a peak of $1.4 trillion at the beginning of the Obama administration, to $585 billion in 2016 (Obama’s last year in office), will be back up to $960 billion this fiscal year, and back over $1 trillion in 2020. (Here’s the New York Times piece detailing those numbers.) Trump is currently floating various tax cuts for the rich and the poor that will presumably worsen those projections, if passed. As the Times piece reported: