you can put verification code in setter as if you want a 
variable for storing weight you never want weight -ve So 
write the code that prevent -ve entry of varible value in 
setter method

Using getter and making your variable private you can be 
sure that nobody can access it directly from outside.

Before get into the answer, we gotta know something 
prior...! "JavaBeans".
JavaBeans are java classes that have properties. For our 
purpose, think of properties as private instance variables. 
since they're private, the only way they can be accessed 
from outside of their class is through 'methods'in the 
class. 
The methods that change a propertiy's value are called 
setter methods, and the methods that retrieve a property's 
value are called getter methods.