Why You Should Use Accessors, Not Public Fields

• 1) You can put constraints on values

  
  
  public void setSpeed(double newSpeed) {if (newSpeed < 0) {
  sendErrorMessage(...);
  newSpeed = Math.abs(newSpeed);
  }
  speed = newSpeed;
  }
  
  • If users of your class accessed the fields directly, then they would each be responsible for checking constraints.

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