5- Catching Exceptions

Jun 18, 2026 03:47 · 3:51 · English · Whisper Turbo · 2 Speakers

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Indeks predavanja

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S… Speaker 2 (5- Catching Exceptions)

Now let's see how we can cache exceptions.

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So let's create a file reader object.

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Reader,

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we set it to a new file reader.

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And here we type file .txt,

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the name doesn't matter.

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Now right after this line,

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we print a message like file open.

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Now we have a compilation error because we haven't handled the file

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not found exception.

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To do this,

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we should wrap this code inside a try block.

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So we type try

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followed by curly braces to indicate a block of code.

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Then we move these lines inside this try block.

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Now,

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right after the try block,

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we type the catch clause.

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And here in parentheses,

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we specify the type of exception we want to catch.

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In this case,

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file not found exception.

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Then we give it a name.

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By convention,

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we call this object x,

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as in short for exception.

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So this x object is an instance of the file not found

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exception.

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It's an object that contains information about this exception.

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So,

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here we add another block,

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and in this block,

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we print a friendly message to the user.

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Something like,

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file does not exist.

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Now,

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let's run the program.

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Our program didn't crash.

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This is the proper way to handle checked exceptions.

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Now, we can also get the message from this exception object.

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So,

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we type x dot get message.

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This returns a string,

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so we can print it on the terminal,

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file dot txt,

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no such file or directory.

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This error message is defined in the file not found exception class.

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Okay?

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Now,

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what happened to this statement over here?

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We tried to print file open,

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but we are not seeing that message.

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Here's the reason.

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When a line throws an exception,

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the control moves to the catch block for that exception.

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So the code that we have after the offending line will

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not be executed.

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However,

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if I take this line and put it after our try catch block,

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it will get executed.

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Take a look.

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So now we have file open.

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So this is how we can catch exceptions in Java.

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Now let me show you a trick.

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I'm going to take this line out of our try block,

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put it over here.

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and then delete the rest of this code.

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So let's say you're creating a file reader object and the

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compiler is complaining that we haven't handled this checked exception.

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Now,

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we don't have to manually type a try catch block.

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We can put the carrot over here,

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press alt and enter and select surround with

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try catch.

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Isn't that beautiful?

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So IntelliJ automatically created this try catch block for us.

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Now here we're calling the print stack trace method of this exception object.

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This will show us something like what you saw before.

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So we got an exception of type file not

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found exception.

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Here's the error associated with this exception.

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Now look at the stack trace.

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This exception was thrown from the file input stream

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class.

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This is not part of our project.

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This is part of the standard Java library.

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So in our show method,

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when we try to create a new file reader,

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the constructor of the file reader was called and then internally this class

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works with another class called file input stream.

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Here we have a few method calls and this is where the exception

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was thrown.

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So sometimes you see a long slack trace because of the method calls

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in the Java standard library or other libraries that you use.

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Next we're going to talk about catching multiple types of exceptions.

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