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Thinking in Java
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Passing exceptions to the console

In simple programs, like many of those in this book, the easiest way to preserve the exceptions without writing a lot of code is to pass them out of main( ) to the console. For example, if you want to open a file for reading (something you’ll learn about in detail in Chapter 12), you must open and close a FileInputStream, which throws exceptions. For a simple program, you can do this (you’ll see this approach used in numerous places throughout this book):

//: c09:MainException.java
import java.io.*;

public class MainException {
  // Pass all exceptions to the console:
  public static void main(String[] args) throws Exception {
    // Open the file:
    FileInputStream file =
      new FileInputStream("MainException.java");
    // Use the file ...
    // Close the file:
    file.close();
  }
} ///:~


Note that main( ) is also a method that may have an exception specification, and here the type of exception is Exception, the root class of all checked exceptions. By passing it out to the console, you are relieved from writing try-catch clauses within the body of main( ). (Unfortunately, file I/O is significantly more complex than it would appear to be from this example, so don’t get too excited until after you’ve read Chapter 12).
Thinking in Java
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   Reproduced courtesy of Bruce Eckel, MindView, Inc. Design by Interspire