Exception throwing

[John Stark]

Hi,

This is from an Enthuware question:

import java.io.*;
import java.sql.*;

class Main
{
	public static void main(String[] args) throws Exception
	{
		Main m = new Main();
		m.m1();	
	}

	void m1() throws Exception
	{
		try
		{
			throw new IOException();
		}
		catch (IOException e)
		{
			throw new SQLException();
		}
		finally
		{
			throw new CloneNotSupportedException();
		}
	}
}

When I run the code I get:

Exception in thread "main" java.lang.CloneNotSupportedException
at Main.m1(Main.java:24)
at Main.main(Main.java:9)


So an SQLException should be thrown from within the catch block, but since the finally block is always executed a CloneNotSupportedException is thrown as well.
My question is what happens to the SQLException?

Handling just the CloneNotSupportedException when calling m1() compiles fine:

import java.io.*;
import java.sql.*;

class Main
{
	public static void main(String[] args) 
	{
		Main m = new Main();
		try
		{
			m.m1();	
		}
		catch (CloneNotSupportedException e)
		{
			System.out.println("CloneNotSupportedException");
		}
	}

	void m1() throws CloneNotSupportedException
	{
		try
		{
			throw new IOException();
		}
		catch (IOException e)
		{
			throw new SQLException();
		}
		finally
		{
			throw new CloneNotSupportedException();
		}
	}
}

Running this code just results in the output "CloneNotSupportedException".
It seems like an SQLException is thrown in the catch block but never handled or declared.

Thanks,

John

[Stephan van Hulst]

The exception thrown in the try block is simply ignored and "overruled" by the exception thrown in the finally block.

This is the reason why finally blocks should never terminate abnormally. Whenever you have a checked exception in a finally block, catch it and log it. This way, you will get a notification in your log file why the finally block failed, and the exception in the try block will propagate normally.

[John Stark]

Good idea. Thanks Stephan.

John