6- Catching Multiple Types of Exceptions

Jun 18, 2026 04:21 · 4:28 · English · Whisper Turbo · 2 speakers

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Lecture Index

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Sometimes we need to catch multiple types of exceptions.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

For example,

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after reading a file,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

let's call reader .read.

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This reads one character and returns its numeric value.

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So let's store it in a variable called value.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Now here we have another compilation error because we haven't

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handled the IO exception.

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So this read method may throw an IO exception if it cannot read

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data from this file.

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To solve this problem,

0:30

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we need to type another catch clause here.

0:33

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So catch,

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like here we want to catch an IO exception,

0:36

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

we give it a name,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

and in this block,

0:40

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we can print a message like,

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could not read data.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

The exception is gone.

0:47

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Now we have multiple catch blocks,

0:49

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

and each catch block targets a specific type

0:53

S… Speaker 2 (6- Catching Multiple Types of Exceptions)

of exception.

0:54

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So only one of these will be executed.

0:57

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

In this case,

0:58

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

we try to open a file that doesn't exist,

1:01

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

so this line will throw a file not found exception,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

and this catch block will catch that exception.

1:08

S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Now,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

the code inside this catch block will get executed,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

and after that,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

the control will move over here.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So this second catch block will get ignored,

1:18

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

okay?

1:18

S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So we have multiple catch blocks,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

and each catch block targets a specific type of exception.

1:23

S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Now,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

does the order of these catch blocks matter?

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Sometimes it does.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So if I move this catch block over here,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

you see a compilation error.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

The Java compiler is saying that we have already caught the

1:38

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file not found exception.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

What does this mean?

1:40

S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Well,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

let's look at the documentation for the file not found exception class.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So we type Java file not found exception.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Here it is.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Okay.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So this class extends the IOException class.

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And that means,

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if we have a catch clause for an IOException,

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we don't need this FindNotFoundException.

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This is the polymorphism principle of object -oriented programming.

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We talked about this in the second part of this course.

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Let me show you.

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If I have a variable of type IOException,

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let's call it X,

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I can set this variable to a new instance of IOException or

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any classes that extend the IOException class.

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So we can set this to a new file not found exception.

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This is polymorphism.

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An object may take different forms.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

So,

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if you have a catch clause,

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to catch an I .O .Exception,

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this catch clause can catch an I .O .Exception or any of its derivatives,

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any classes that extend the I .O .Exception class.

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Okay?

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Now sometimes we want to treat these exceptions the same way,

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for example here we can display a generic error message,

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but other times we want to handle them differently.

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If that is the case,

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then we need to bring back this catch clause and put

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it before the first catch clause,

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so now if we get a find not found exception,

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we can print a message like,

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file does not exist.

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So we are giving the user a more specific error message.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Now,

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as another example,

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let's create a new simple date format object

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and call the parse method.

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Now here we have another compilation error,

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because this parse method may throw an exception of type parseException.

3:34

S… Speaker 2 (6- Catching Multiple Types of Exceptions)

Now,

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we can put the carrot over here,

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press alt and enter,

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and have IntelliJ add a catch clause for us.

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S… Speaker 2 (6- Catching Multiple Types of Exceptions)

There you go.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

So it's right here.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Now we have three catch clauses.

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

Let's say we want to treat all of these the same way.

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So first we can get rid of the file not found exception.

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Now we have two catch clauses.

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We can combine this using a vertical bar.

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So right after IO exception,

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S… Speaker 1 (6- Catching Multiple Types of Exceptions)

we type a vertical bar,

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then we type parse exception,

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and with this we don't need the second catch clause.

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So this block can catch exceptions of type ioException or

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parseException.

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So these are different ways to catch multiple exceptions.

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The approach you take really depends on your application and its requirements.

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Next we're going to talk about the finally block.

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