java - Which way of setting fields value is better and why? -

this question can stupid, want know, there difference?

class a{     // common code     private int field;     public void setfield(int field){          this.field = field;     }      //way 1     public a(int field){         this.field = field;     }      //way 2     public a(int field){         setfield(field);     } } 

way 2 better because gives unified way of setting variable value. brings in risk, because you're calling overrideable method in constructor. right syntax using final keyword:

public final void setfield(int field){      this.field = field; }  //way 2 public a(int field){     setfield(field); } 

with final method not overriden. if can not afford have final method, don't call setter in constructor. it's strange override setter.

this because may want change setter later:

• add argument checks , throw illegalargumentexception when required.
• add counter
• notify observers (in observable pattern)
• make synchronized block provide thread-safety
• ...

and have in single place. implementation of dry principle.

public final synchronized void setfield(int field){     if (0 <= field && field <= max_value) {         this.field = field;     } else {         throw new illegalargumentexception();     }    }  //still has benefits of setter public a(int field){     setfield(field); }  = new a(-1) //throws illegalargumentexception 

don't worry optimization , expenses of method call. jvm can optimize such code inlining methods.

what makes development slower searching bug. method helps make less mistakes , easier maintain code.