This post explains how to programmatically get access to all printers configured in a machine. Java provides lookup facitlity through PrintServiceLookup class. This class has static methods through which we can get a reference to all the printers. We use the lookupPrintServices method in the PrintServiceLookup class. The api definition is as shown below public…… Continue reading Getting access to all printers configured in machine
Executing scripts written in a file using java
This post explain how to execute javascript code stored in a file. We create an instance of FileReader representing the physical file and pass it to eval method of an instance of ScriptEngine. Please refer to previous posts to know more about ScriptEngine and ScriptEngineManager The javascript code in the file that has to be…… Continue reading Executing scripts written in a file using java
Executing scripts using java
This post explain how to execute code written in scripting language like php or javascript etc in java. The scripts are executed by calling eval on an instance of ScriptEngine interface. An instance of ScriptEngine is used to represent scripting language specific engines. For example in case of JavaScript, Mozilla Rhino provided out of the…… Continue reading Executing scripts using java
Getting access to default printer
This post explains how to programmatically get access to a printer configured as default printer in a machine. Java provides PrintServiceLookup class, which provides static methods through which we can get a reference to the printer. Each printer installed in a machine is represented by an instance of PrintService interface. The PrintService interface provides methods…… Continue reading Getting access to default printer
Writing json data using Jackson JsonGenerator
The below post explains how to write json data to file using JsonGenerator. JsonGenerator writes the data to a file in streaming way, helping the developer using the api to avoid creating an object representation of the data. We can get an instance of JsonGenerator with the help of an instance of JsonFactory as shown…… Continue reading Writing json data using Jackson JsonGenerator
PushBackReader Demo
This post explains PushBackReader class in java. This reader allows us to put the data read from the input stream back into the stream and reread it again. The below explains how to use it Main Class package IO; import java.io.PushbackReader; import java.io.StringReader; public class PushBackReaderDemo { public static void main(String[] args) throws Exception {…… Continue reading PushBackReader Demo
Intercepting hibernate CRUD operations
This post explains how to intercept hibernate create, read, update and delete operations, so that we can add our own logic that has to be performaned before CRUD operations. The different use case where we need to intercept these hibernate operations are as follows 1) Every entity in the applications has common fields for example…… Continue reading Intercepting hibernate CRUD operations
UnMarshaling Json file
This post explains unmarshalling a object information stored in json format to java object . This can be achieved with the help of ObjectMapper provided by jackson databind package. To explain with an example we will use the below pojo objects User public class User { private Name name; private String ssn; private String sex;…… Continue reading UnMarshaling Json file
Marshaling Java Object
This post explains marshalling a java object to json format and storing it to a file. This can be achieved with the help of ObjectMapper provided by jackson databind package. To explain with an example we will use the below pojo objects User public class User { private Name name; private String ssn; private String…… Continue reading Marshaling Java Object
Retrieving JsonParser Settings
This post explains how to get json parser default settings. import java.io.File; import java.io.IOException; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonParser.Feature; public class ProcessingDemo2 { public static void main(String[] args) throws JsonParseException, IOException { File file = new File(“jsondata.json”); JsonFactory jsonFactory = new JsonFactory(); JsonParser jsonParser = jsonFactory.createParser(file); for(Feature feature : Feature.values()) { System.out.println(feature.name()…… Continue reading Retrieving JsonParser Settings
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