Postal Code In Database - Leading Zeros Been Trim

I got situation where i have postal code as 0009 in database and the use is entering 0009 but somehow in my java code it only reading 9 from the xml file
 
This is how i define getter and setter :
 
When I debug the code i get this :

passed postalcode 9
 
if a user entered 0009 I what it to remain 0009
 
Java Code:

public String Postalcode="";  
public void setPostalcode(String Postalcode) { this.Postalcode = Postalcode; } 
public String getPostalcode() { return Postalcode; }