Using finalize() to detect an object that hasn't been properly cleaned up : Finalize « Language Basics « Java

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Using finalize() to detect an object that hasn't been properly cleaned up

// : c04:TerminationCondition.java
// Using finalize() to detect an object that hasn't been properly cleaned up.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
class Book {
  boolean checkedOut = false;

  Book(boolean checkOut) {
    checkedOut = checkOut;
  }

  void checkIn() {
    checkedOut = false;
  }

  public void finalize() {
    if (checkedOut)
      System.out.println("Error: checked out");
  }
}

public class TerminationCondition {
  public static void main(String[] args) {
    Book novel = new Book(true);
    // Proper cleanup:
    novel.checkIn();
    // Drop the reference, forget to clean up:
    new Book(true);
    // Force garbage collection & finalization:
    System.gc();
  }
} ///:~



           
       

Related examples in the same category

1.	Ensuring proper cleanup
2.	Demonstrate how finalize() methods and shutdownHooks interact