How to implement sort class

You have to implement Comparable / compareTo method.

Use Comparator Interface from java.util package to sort in more than one way......

Use the compare(T t1, T t2) method of Comparator Eg:

Here is an example from site http://www.mkyong.com

import java.util.Comparator;

public class Fruit{

    private String fruitName;
    private String fruitDesc;
    private int quantity;

    public Fruit(String fruitName, String fruitDesc, int quantity) {
        super();
        this.fruitName = fruitName;
        this.fruitDesc = fruitDesc;
        this.quantity = quantity;
    }

    public String getFruitName() {
        return fruitName;
    }
    public void setFruitName(String fruitName) {
        this.fruitName = fruitName;
    }
    public String getFruitDesc() {
        return fruitDesc;
    }
    public void setFruitDesc(String fruitDesc) {
        this.fruitDesc = fruitDesc;
    }
    public int getQuantity() {
        return quantity;
    }
    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }



    public static Comparator<Fruit> FruitNameComparator 
                          = new Comparator<Fruit>() {

        public int compare(Fruit fruit1, Fruit fruit2) {

          String fruitName1 = fruit1.getFruitName().toUpperCase();
          String fruitName2 = fruit2.getFruitName().toUpperCase();

          //ascending order
          return fruitName1.compareTo(fruitName2);

          //descending order
          //return fruitName2.compareTo(fruitName1);
        }

    };
}

Compare both types. If the comparison is different from 0, return it as a result. If equal to 0, then compare the names.

Note that:

• Extending Object is unnecessary: it's the default
• Fields should start with a lower-case letter: name, type na dnot Name, Type
• Your class should implement Comparable<FileType>
• I would choose another name for the class: It's not a file type, but a file name associated to a file type
• I would use an enum rather than a String for file types, since you only have two valid instances of file types

• You should never ignore exceptions like you're doing. BTW, if this exception occurs, it could lead to a NullPointerException. Wrap the exception into a runtime exception and throw this runtime exception:

  catch(UnsupportedEncodingException e) {
      throw new RuntimeException(e);
  }
  

• Your compareTo method doesn't handle null names, although the default constructor assigns null to the name. Fix the method or the constructor. It seems to me that a file name should never be null, so I would fix the constructor.

You first compare the type and then the decoded name. I cached the decodedFileName value directly in the class to prevent calling URLDecoder.decode too much.

private class FileType extends Object implements Comparable<FileType>{
    private String name;
    private String decodedFileName;
    private String type;
    public FileType(String n, String t) {
        name = n;
        try {
            decodedFileName = URLDecoder.decode(this.name, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }           
        type = t;
    }
    public int compareTo(FileType other) {
        int result = type.compareToIgnoreCase(other.type);
        if (result == 0){
            result = decodedFileName.compareToIgnoreCase(other.decodedFileName);
        }
        return result;
    }
}

if you have only two types, why dont make them enum?
then first you compare type.ordinal, if there are equal then compare names, and also prevents from putting unwanted values there