Item 14 - In public classes, use accessor methods, not public fields

From Effective Java 2/e by Joshua Bloch

  • If a class is accessible outside its package, provide accessor methods
  • if a class is package-private or is a private nested class, there is nothing inherently wrong with exposing its data fields
// Encapsulation of data by accessor methods and mutators
class Point {
   private double x;
   private double y;

   public Point(double x, double y) {
      this.x = x;
      this.y = y;

   public double getX() { return x; }
   public void setX(double x) { this.x = x; }

   public double getY() { return y; }
   public void setY(double y) { this.y = y; }
  • While it’s never a good idea for a public class to expose fields directly, it is less harmful if the fields are immutable.
// Public class with exposed immutable fields - questionable
public final class Time {
   public final int hour;
   public final int minute;

   public Time(int hour, int minute) {
      this.hour = hour;
      this.minute = minute;

Posted by The Finest Artist