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
Streaming two json files in an order using JsonParserSequence
This post explains how to stream two files in a particular order Main Class 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.JsonToken; import com.fasterxml.jackson.core.util.JsonParserSequence; public class ProcessingDemo3 { public static void main(String[] args) throws JsonParseException, IOException { File file1 = new File(“jsondata.json”); File file2 = new File(“jsondata1.json”); JsonFactory jsonFactory = new…… Continue reading Streaming two json files in an order using JsonParserSequence
Reading JSON in a streaming way
This post explain how to stream a json file. We need to create an instance of JsonFactory, as shown below JsonFactory jsonFactory = new JsonFactory(); by which we can create a parser instance (i.e., JsonParser) to read the json file, as shown below JsonParser jsonParser = jsonFactory.createParser(file); Each element whether start and end of the…… Continue reading Reading JSON in a streaming way
Unit testing method exceptions
Sometime we have to test whether a method throws proper and required exceptions or not. One way of testing is placing the method call (to be tested) inside a try catch block, as shown below try { class2.method1(); fail(“Should have thrown exception”); } catch(IllegalArgumentException excep) { } catch(Exception excep) { fail(“Should have thrown IllegalArgumentException exception”);…… Continue reading Unit testing method exceptions
Setting timeout for test methods
Junit offers us the option to set timeout for test methods. If a test methods doesnt complete within specified time limit, an exception is thrown failing the test case. The use case scenario where this feature can be used is for example testing the performance of a method. The below code shows you how to…… Continue reading Setting timeout for test methods
Making JUnit ignore test methods
If we want JUnit to ignore certain test methods we can do that by using the @Ignore annotation applied on the methods that has to be ignored. The below test class tests a functionality of a calculator CalculatorTest package Package1; import static org.junit.Assert.assertEquals; import org.junit.Ignore; import org.junit.Test; @Ignore public class CalculatorTest { @Test public void…… Continue reading Making JUnit ignore test methods
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