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POJava - Get/set methods receiving and returning "null"
 

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    <p>I'm a beginner in Java. I'm trying, for training purpose, to build myself a chess game application. Within my class Case, that will be used to instanciate all the 64 cases of my board, I write get/set methods to find if there's a Piece occupant in the instances of the case.</p> <p>I read that returning "null" is a bad practice, so I throw an exception instead to signify that the case is free. But, I wonder how to set the occupant's pointer to "null"; can I simply push "null" as a parameter when I will call this method?</p> <p>Also, could taking/returning "null" be an acceptable/good practice?</p> <pre><code>public Piece getOccupant(){ if (this.occupant == null) throw new IllegalArgumentException(this.occupant + " is Empty"); return this.occupant; } public void setOccupant(Piece newOccupant){ this.occupant = newOccupant; } </code></pre> <p>Thanks!</p> <p>[Update]</p> <p>Thanks to all of your for your comments, ideas, corrections and recommendations. Here is the updated version of my code for this part, and I feel satisfied with it, as it served its purpose (increase my understanding thru practice).</p> <pre><code>/* * Modifiers of Occupant */ /** * Used to find if a Piece is located in this Cell * @return a Piece reference to the occupant. Will send a * null pointer if cell is empty */ public Piece getOccupant(){ return this.occupant; } /** * Used to set a new occupant in the Cell. * @param newOccupant is a reference to a Piece instance, * and should be set to null if the cell is emptied, or using * the method clear(). */ public void setOccupant(Piece newOccupant){ this.occupant = newOccupant; } /** * Used to verify if a Cell is empty of any occupant * @return true if cell is empty. */ public boolean isEmpty(){ if(this.occupant == null) return true; return false; } /** * Free the cell of any occupant, if any were */ public void clear(){ this.occupant = null; } </code></pre>
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    1. USAntoineG
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    1. COMaybe I'm wrong, but I don't see why it would be bad to return null in this situation if the cell has no occupants. 1+ for your desire to write better code!
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    2. COPerhaps its just me, but throwing an IllegalArgumentException in a method that doesn't have any arguments is not appropriate.
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    3. COPlease do not have an API that can return null. This means you will need to check every time you use it.
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      1. USThorbjørn Ravn Andersen
 

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