Java immutable (from: http://stackoverflow.com/questions/6927763/immutable-type-public-final-fields-vs-getter)

immu.java

interface Immu { String getA() ; String getB ( ) }

Immu immu ( final String a , final String b )
{
       /* validation of a and b */
       return new Immu ( )
       {
              public String getA ( ) { return a ; }

              public String getB ( ) { return b ; }
       }
}