Question

1. Assume you are writing code to serialize a group of Student objects to an XML document. What Java API method will you call to execute the serialization process? NOTE: You must use the XML serialization/deserialization method/concepts presented in this course.

2. Assume that the list of exception types below may occur within the scope of a method. In order to properly handle these exceptions, each type must be handled individually and separately.  Arrange the exception types in the order in which your code must address them to insure that no type "falls through" to be processed along with any other type. (HINT: These are all Java API exception types.)

5 points

IOException

Exception

FileSystemException  

NoSuchFileException

Answer 1

1. To Serialize an object to XML we need to Create an XMLEncoder Class Object which is available in "java.beans" package. After Creating the Object we can use writeObject() to encode the Object.

To Better Understand the Concept Lets consider the following Student Class:

Student.java

import java.io.*; import java.util.*; public class Student {      private String name;    private String HNo;    private float gpa;       public Student(){}      public Student(String name, String Hno,float gpa) {              this.name = name;        this.HNo = Hno;        this.gpa = gpa;       }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }       public String getHNo() {        return HNo;    }    public void setHNo(String Hno) {        this.HNo = Hno;    }    public float getGpa() {        return gpa;    }    public void setGpa(float gpa) {            this.gpa = gpa;    } }

We Use the Following SerializeToXML class that use the XMLEncoder to Encode Objects to XML files

import java.io.*; import java.util.*; import java.beans.XMLEncoder; public class SerializeToXML {      private static final String SERIALIZED_FILE_NAME="student.xml";    public static void main(String args[]){        Student s1=new Student("John","123",3.7f);        Student s2=new Student("Smith","124",3.7f);        Student s3=new Student("Ben","125",3.7f);        Student s4=new Student("Tom","126",3.7f);        List sList=new ArrayList();        sList.add(s1);        sList.add(s2);        sList.add(s3);        sList.add(s4);        XMLEncoder encoder=null;        try{        encoder=new XMLEncoder(new BufferedOutputStream(new FileOutputStream(SERIALIZED_FILE_NAME)));        }catch(FileNotFoundException fileNotFound){            System.out.println("ERROR: While Creating or Opening the File dvd.xml");        }        encoder.writeObject(s1);        encoder.writeObject(s2);        encoder.writeObject(s3);        encoder.writeObject(s4);        encoder.close();    } }

Output:

After Execution the XML file is Generated in the Present Working Directory.

The Created XML file is:

2. The relationship between The four Exceptions is in the following Hierarchy.

• java.lang.Exception
• • java.io.IOException
  • • java.nio.file.FileSystemException
    • • java.nio.file.NoSuchFileException

So the Correct order to Handel the Four exceptions is First  NoSuchFileException, then FileSystemException, then IOException and finally Exception