Paying attention to exceptions in constructors

 
// : c09:Cleanup.java
// Paying attention to exceptions in constructors.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

class InputFile {
  private BufferedReader in;

  public InputFile(String fname) throws Exception {
    try {
      in = new BufferedReader(new FileReader(fname));
      // Other code that might throw exceptions
    } catch (FileNotFoundException e) {
      System.err.println("Could not open " + fname);
      // Wasn't open, so don't close it
      throw e;
    } catch (Exception e) {
      // All other exceptions must close it
      try {
        in.close();
      } catch (IOException e2) {
        System.err.println("in.close() unsuccessful");
      }
      throw e; // Rethrow
    } finally {
      // Don't close it here!!!
    }
  }

  public String getLine() {
    String s;
    try {
      s = in.readLine();
    } catch (IOException e) {
      throw new RuntimeException("readLine() failed");
    }
    return s;
  }

  public void dispose() {
    try {
      in.close();
      System.out.println("dispose() successful");
    } catch (IOException e2) {
      throw new RuntimeException("in.close() failed");
    }
  }
}

public class Cleanup {

  public static void main(String[] args) {
    try {
      InputFile in = new InputFile("Cleanup.java");
      String s;
      int i = 1;
      while ((s = in.getLine()) != null)
        ; // Perform line-by-line processing here...
      in.dispose();
    } catch (Exception e) {
      System.err.println("Caught Exception in main");
      e.printStackTrace();
    }
  }
} ///:~

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7.	Show that if your class has no constructors, your superclass constructors still get called
8.	Constructor calls during inheritance
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Paying attention to exceptions in constructors : Constructor « Class « Java

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