Chapter 9

class MyException extends Exception {

	MyException() throws MyException {
		System.out.println("one");
		throw new MyException("three");
	}

	MyException(String s) {
		System.out.println("two: " + s);
	}

}

public class Except {

	Except() {
		try {
			throw new MyException();
		} catch (MyException e) {
			System.out.println("MyException:
                               " + e);
		} catch (Exception e) {
			System.out.println("Exception: " 
                               + e);
		} finally {
			System.out.println("finally");
		}
	}

	public static void main(String[] args) 
                        throws MyException {
		new Except();
		System.out.println("done");
	}

}

class MyException extends Exception {

	MyException() {
		super();
		System.out.println("MyException");
	}

	MyException(String s) {
		super(s);
		System.out.println("MyException: " 
                           + s);
		System.exit(0);
	}

}

public class Except {

	public static void main(String[] args) {
		new MyException("Testing");
		new MyException();
	}

}

class MyException extends Exception {

	MyException() {
		this("Testing");
		System.out.println("one");
	}

	MyException(String s) {
		super(s);
		System.out.println("two: " + s);
	}

}

public class Except {

	Except() {
		try {
			throw new MyException();
		} catch (Exception e) {
			System.out.println("Caught: " 
                               + e);
		}
	}

	public static void main(String[] args)
                        throws MyException {
		new Except();
		System.out.println("done");
	}

}

class MyException extends Exception {

	MyException() {
		System.out.println("one");
	}

	MyException(String s) {
		System.out.println("two: " + s);
	}

}

public class Except {

	Except() {
		try {
			throw new MyException("Test");
		} catch (MyException e) {
			System.out.println("MyException:
                               " + e);
		} catch (Exception e) {
			System.out.println("Exception: "
                               + e);
		}
	}

	public static void main(String[] args)
                        throws MyException {
		new Except();
		System.out.println("done");
	}

}

class MyException extends Exception {

	MyException() {
		System.out.println("one");
	}

	MyException(String s) {
		System.out.println("two: " + s);
	}

}

public class Except {

	Except() {
		try {
			throw new MyException("Test");
		} catch (MyException e) {
			System.out.println("MyException:
                               " + e);
		} catch (Exception e) {
			System.out.println("Exception: " 
                               + e);
		} finally {
			System.out.println("finally");
		}
	}

	public static void main(String[] args)
                        throws MyException {
		new Except();
		System.out.println("done");
	}

}

class MyException extends Exception {

	MyException() {
		System.out.println("one");
	}

	MyException(String s) {
		System.out.println("two: " + s);
	}

}

public class Except {

	Except() {
		try {
			if (4 > 40)
				throw
					new MyException("Test");
		} catch (MyException e) {
			System.out.println("MyException:
                               " + e);
		} catch (Exception e) {
			System.out.println("Exception: " 
                               + e);
		} finally {
			System.out.println("finally");
		}
	}

	public static void main(String[] args)
                        throws MyException {
		new Except();
		System.out.println("done");
	}

}

public class Except {

	Except() {
		for (int i=0; i<5; i++)
			tryme(i);
	}

	private void tryme(int n) {
		try {
			if (n % 3 == 0)
				throw new Exception(n + 
                 " is a multiple of three");
			else
				System.out.println("n = " +
                                    n);
		} catch (Exception e) {
			System.out.println(e.getMessage());
		}
	}

	public static void main(String[] args) {
		new Except();
	}

}

public class Except {

	Except() {
		for (int i=0; i<5; i++)
			try {
				tryme(i);
			} catch (Exception e) {
				System.out.println(e.getMessage());
			}
	}

	private void tryme(int n)
                         throws Exception {
		if (n % 3 != 0)
			throw new Exception(n + 
             " is not a multiple of three");
		
			System.out.println("n = " + n);
	}

	public static void main(String[] args) {
		new Except();
	}

}

public class Exceptions {

	Exceptions() {
		try {
			for (int n = 3; n >= -3; n--)
				System.out.println(100 / n);
		} catch (ArithmeticException e) {
			System.out.println("0-Divide!");
		} finally {
			System.out.println("Done");
		}
	}

	public static void main(String[] args) {
		new Exceptions();
	}
}

1. If an exception is thrown within a try block, the finally clause always executes.
2. If no exception is thrown within a try block, the finally clause always executes.
3. If an exception is thrown within an exception handler, the finally clause always executes.
4. If an exception is thrown within a finally block, the exception is propagated out of the finally block, and the finally block does not complete its execution.

1. If a method may throw an exception, it must either catch it or use a throws clause
2. If a method may throw an exception, it must catch it
3. A method may include a throws clause for an exception that it does not throw
4. A method may not include a throws clause unless it actually throws an uncaught exception

1. Unchecked exceptions should be handled by the code you write.
2. Checked exceptions must be handled by code that you write.
3. You need not provide an exception handler for an unchecked exception.
4. You need not provide an exception handler for a checked exception.
5. You need not provide a catch clause for a checked exception if you provide a throws clause.
6. Every Java program has the potential for throwing an unchecked exception.