• Checked exception, compiler ensures that the checked exeption is caught or is declared in a throws clause
  • All classes that inherit from class Exception but not class RuntimeException
• Uncheck exception, Java compiler does not check the code to determine whether an unchecked exception is caught or declared
  • Errors and runtime exceptions

try
{
	//do something
}
catch (Exception1 e)
{
	//exception-handling statements
}
...
catch (ExceptionN e)
{
	//exception-handling statements
}
finally
{
	//statements
	//resource-release statements
}
			

• finally block will execute if a try block exits by using a return, break or continue statement
• finally block will not execute if the application exits earyly from a try block by calling method System.exit

public class E
{
	public static int quotient(int numerator, int denominator) throws ArithmeticException
	{
		return numerator/denominator;
	}

	public static void main(String args[])
	{
		try
		{
			quotient(10, 1);
		}
		catch (Exception e)
		{
			System.out.println(e.getClass().getName());
			System.out.println(e);
			System.out.println(e.getMessage());
			System.out.println(e.getStackTrace());
		}
		finally
		{
			System.out.println("Release resource ...");
		}
	}
}
			

• For a function, either catch exception inside the function, or throws exception in throws clause, which appears after the methods's parameter list and before the method's body
• Checked exception requires throws clause, uncheck exception does not require a throws declaration as well

import java.io.*;

public class E
{
	public static void f1()
	{
		throw new ArithmeticException();//uncheck exception
	}

	public static void f2() throws IOException
	{
		throw new IOException();//checked exception
	}

	public static void main(String args[])
	{
		try
		{
			f1();
		}
		catch (Exception e)
		{
			System.out.println(e);
		}
		finally
		{
			System.out.println("Release resource ...");
		}

		try
		{
			f2();
		}
		catch (Exception e)
		{
			System.out.println(e);
		}
		finally
		{
			System.out.println("Release resource ...");
		}
	}
}
			

public class ExceptionADT extends Exception
{
	@Override
	public String getMessage()
	{
		Exception e = new Exception("Exception");
		return "ExceptionADT: "+e;
	}
}
			

public class E
{
	public static void main(String args[])
	{
		try
		{
			throw new ExceptionADT();
		}
		catch (ExceptionADT e)
		{
			System.out.println(e.getMessage());
		}
		finally
		{
			System.out.println("Release resource ...");
		}
	}
}
			

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