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Programming Articles
Page 2314 of 2547
How to get the values of a key using the JsonPointer interface in Java?
The JSONPointer is a standard that defines a string syntax that can be used to access a particular key value in the JSON document. An instance of JSONPointer can be created by calling the static factory method createPointer() on the Json class. In the JSONPointer, every string syntax is prefixed with “/”. We can get the value of a key by calling the getValue() method on the JsonPointer object.JSON fileExampleimport javax.json.*; import java.io.*; public class JsonPointerTest { public static void main(String[] args) throws Exception { JsonReader jsonReader = Json.createReader(new FileReader("simple.json")); ...
Read MoreImportance of the JsonPatch interface in Java?
The JsonPatch interface is a format for storing a sequence of operations that can be applied to the target JSON structure. There are few operations like add, remove, replace, copy, move and test can be stored in JsonPath and operated on JSON structure. The JsonPatchBuilder interface can be used for constructing a JSON patch using the Json.createPatchBuilder().JSON fileExampleimport java.io.*; import javax.json.Json; import javax.json.JsonPatch; import javax.json.JsonPatchBuilder; import javax.json.JsonReader; import javax.json.JsonStructure; public class JsonPatchTest { public static void main(String[] args) throws Exception { JsonPatchBuilder jsonPatchBuilder = Json.createPatchBuilder(); JsonPatch jsonPatch = jsonPatchBuilder.add("/postalCode", "500072").remove("/age").build(); JsonReader reader = Json.createReader(new FileReader("simple.json")); ...
Read MoreHow to create a JSON using JsonObjectBuilder and JsonArrayBuilder in Java?
The JsonObjectBuilder can be used for creating JsonObject models whereas the JsonArrayBuilder can be used for creating JsonArray models. The JsonObjectBuilder can be created using the Json class, it contains methods to create the builder object and build an empty JsonObject instance using the Json.createObjectBuilder().build(). The JsonArrayBuilder can be created using the Json class, it contains methods to create the builder object and build an empty JsonArray instance using Json.createArrayBuilder().build().Exampleimport java.io.*; import javax.json.*; public class JsonObjectTest { public static void main(String[] args) { JsonObject empObject = Json.createObjectBuilder().add("empName", "Jai") ...
Read MoreJava Virtual Machine (JVM) Stack Area
Following are some key points to undertstand JVM Stack Area −During the creation of a thread, the Java Virtual Machine creates a separate stack.The JVM performs only two operations upon this stack. The operations are push (i.e insert) and pop (i.e delete).When a thread is currently in execution, the stack associated with it is known as runtime stack.Every method call done by the thread, intermediate calculations, assignment of local variables, calling parameters etc, are stored as an operation in the runtime stack.Once the thread stops or completes executing, the respective part from the stack is deleted.Once all the calls by ...
Read MoreHow to parse a JSON string using Streaming API in Java?
The Streaming API consists of an important interface JsonParser and this interface contains methods to parse JSON in a streaming way and provides forward, read-only access to JSON data. The Json class contains the methods to create parsers from input sources. We can parse a JSON using the static method createParser() of Json class.Syntaxpublic static JsonParser createParser(Reader reader)Exampleimport java.io.*; import javax.json.Json; import javax.json.stream.JsonParser; import javax.json.stream.JsonParser.Event; public class JSONParseringTest { public static void main(String[] args) { String jsonString = "{"name":"Adithya", "employeeId":"115", "age":"30"}"; JsonParser parser = ...
Read MoreHow to create a JSON Object using Object Model in Java?
The javax.json.JsonObject interface can represent an immutable JSON object value and provides an unmodifiable map view to the JSON object name/value mappings. A JsonObject instance can be created from an input source using the static method readObject() of javax.json.JsonReader class and also can be created using the static method createObjectBuilder() of javax.json.Json class.Syntaxpublic static JsonObjectBuilder createObjectBuilder()Exampleimport java.io.*; import javax.json.*; public class JsonObjectTest { public static void main(String[] args) throws Exception { JsonObjectBuilder builder = Json.createObjectBuilder(); builder.add("Name", "Adithya"); builder.add("Designation", "Python ...
Read MoreGetting started with coding
Looking to explore the world of online programming? then, there is good news to all of you!! Currently, there are few online programming websites which offer free services. Tutorialspoint is one such provider. Few years back, Tutorialspoint.com started compiler online service and based on the excellent response, the company has enhanced the service which is renamed as “Coding Ground”. It is a one stop solution for aspiring programmers and IT professionals to start coding in their relevant software without any installation requirement.The biggest technology innovators like Google, Microsoft or Amazon were built due to the consistent effort of programmers as ...
Read MoreImportance of the accumulate() method of JSONObject in Java?
A JSONObject is an unordered collection of a name and value pairs. A few important methods of JSONArray are accumulate(), put(), opt(), append(), write() and etc. The accumulate() method accumulates the values under a key and this method similar to the put() method except if there is an existing object stored under a key then a JSONArray can be stored under a key to hold all of the accumulated values. If there is an existing JSONArray then a new value can be added.Syntaxpublic JSONObject accumulate(java.lang.String key, java.lang.Object value) throws JSONExceptionExampleimport org.json.*; public class JSONAccumulateMethodTest { public static ...
Read MoreHow to convert a JSON object to an enum using Jackson in Java?
A JSONObject can parse the text from String to produce a Map kind of an object. An Enum can be used to define a collection of constants, when we need a predefined list of values which do not represent some kind of numeric or textual data then we can use an enum. We can convert a JSON object to an enum using the readValue() method of ObjectMapper class.In the below example, we can convert/deserialize a JSON object to Java enum using the Jackson library.Exampleimport com.fasterxml.jackson.databind.*; public class JSONToEnumTest { public static void main(String arg[]) throws Exception { ...
Read MoreWhich function should be used to load a package in R, require or library?
The main difference between require and library is that require was designed to use inside functions and library is used to load packages. If a package is not available then library throws an error on the other hand require gives a warning message.Using library> library(xyz) Error in library(xyz) : there is no package called ‘xyz’Using requirerequire(xyz) Loading required package: xyz Warning message: In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE, : there is no package called ‘xyz’Here we can see that the library shows an error and require gives a warning message, since warnings are mostly avoided ...
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