How to add annotations to getter and setter property?

Hi
I have define property as
// Value Date
public void setValueDate(String valDate)
{
sValueDate = valDate;
}
public String getValueDate()
{
return sValueDate;
}
I want to add annotation to check for nulls, length for validation purpose. How to add annotation ?
Thanks in advance

What have you tried? Without more detail, the best we can do is point you here: https://www.google.com/search?q=java+annotations