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As mentioned earlier apart from check the captions we also have something called unchecked exceptions

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.

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So a program can generate either checked or unchecked exceptions the whole thing check exceptions.

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But let's do a quick recap of it.

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We know that there are costs by exception of situations that are simply not under our control.

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Examples would be things like partners or were being down our database being unavailable.

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If you do it checked exception the compan I've got on it is two things.

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First is you must announce that you're throwing the exception by specifying it in the method declaration

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using a gross gross and second is the invoking code must acknowledge the exception by wrapping the calling

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card in a cricut rock or just in done really the exception for the next higher level method to handle

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that next is unshaped exceptions and these are generated by either programming frost or due to some

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internal system writers like out-of-memory others and if they're caused by programming flaws then they're

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referred to as the runtime exceptions.

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But of their culture in general system adder's then they're just referred to as adder's since runtime

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exceptions are due to programming at all.

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You want them to happen mostly or double up on testing time.

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So ideally with good development and testing effort you would want as minimal runtime exceptions as

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possible.

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It there's a GBM deleted under normal conditions and they occur rarely and when they do occur the Jell-O

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program terminates Generally you shouldn't catch on on time exceptions as there are due to programming

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errors usually the recovery from such exceptions is implausible and continued exaggeration would do

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more harm than good.

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But sometimes you might want to catch them too.

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One example would be when you're parsing a response from a web service you encounter a problem parsing

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some piece of data.

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For instance format of a date field might have changed in this because when you try to parse the date

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field you may get an unchecked exception.

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So in this case it would be worthwhile to cast the exception and let the web service provider know about

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it.

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And of course you should seriously run them not to change their API.

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And with regards to errors since there are some abnormal conditions a reasonable application would not

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be expected to catch it.

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So you would almost never catch an error as the name implies these exceptions are not checked by computer

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that you can store them anywhere.

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And the compiler does not bother checking whether or not they are specified in the method declaration

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or whether or not they are handled by the invoking code.

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So that's entirely optional if you want to you can specify them in the declaration and you can also

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handle them but it's not mandatory.

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And so it is entirely up to you shortly we leave them off unchecked exception.

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They have to look at runtime exception.

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We would not look at error as if it is really an abnormal condition and we said we don't want to handle

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it in almost all cases.

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But if you'll recall we did just that and out-of-memory error in one of them was in JVM in dentals chapter

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so at least we have seen an editor being gender Did anyone offered the most on here as exceptions in

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Hedican street and the route you have trouble plus that is a superclass of all exceptions are Natters

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and it has to Sampras's exception I never it it crosses represent errors that were just part of unshipped

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exceptions.

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No exception class has of surprises on one of them is runtime exception runtime exception under subprocess

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represent runtime exceptions that are also discussed as part of unshipped exception.

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As you can see all unshipped exception classes are emphasized in red but all checked exception classes

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are emphasized in book so checked exceptions are all exceptions that are represented by a label or one

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of its surprises with the exception of error or runtime exception or one of their surprises.

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Not get the convention all across all that a person being at odds and with that text editor all of that

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exception classes acceptable.

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And with the next exception know this light also illustrates all that commonly uncontained checked and

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unchecked exceptions.

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Let's quickly review most of them.

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We are really not him or them or the Iowa exception which is a checked exception and all its subclasses

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are related to input output errors like reading from or writing with a missing phone or a server that

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is not responding and you already know about null pointer I'm at a Nick sort of bonce exceptions both

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of which are unchecked exceptions a legal argument the exception is an unchecked exception and it is

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thrown when the method is passed an illegal or an inappropriate argument legal next see this exception

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in our table Glasgow's exception is an unshipped exception is thrown if it tried to cast an object to

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suppress but the object is not really an instance of this obvious number for me the exception is thrown

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if we try to convert a string to a numeric type but the string does not have an appropriate format.

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For instance we get this exception if we apply integer not parsed in method on a string like ABC next

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non-class for Nader is an unchecked exception and it is a subclass of error and it is drawn when classloader

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Kreisler the definition of a class A no definition could be fun.

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Have a lower class definition existed when the class was compiled.

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But it can no longer be found for some reason.

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Finally we already know about out-of-memory error which is a subclass of Woodrell machine at a JVM throws

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it when it is unable to create an object of insufficient memory.

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So those are the most commonly encountered check done unshipped exceptions and you can also read more

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about them from the API.

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Let people pull up the AP I could just show you where you can find the exceptions.

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And here is the API I and here are all the packages on how clicked on the dollar package.

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And here you can see all the interfaces within Jodan package and also all the classes here.

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If you scroll down at the bottom you can see all the exceptions and also the on the ruler the dollar

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package has.

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OK so next let's just go ahead and let's look at the demo of unchecked exception.

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Could demonstrate an exception.

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Let's just go to our next hour Senator Vijender I'm unsure that's a option.

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Illegal argument exception.

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And as mentioned earlier this exception will be gender if the mother is involved with an illegal argument

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.

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For example this method has the parameter destination whose value should be either 0 or 1.

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Now the sentiment that is in work with any other argument value other than zero on one then it would

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be illegal.

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And we can generate an illegal argument exception for that.

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OK.

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So many times methods and constructors have such restrictions on the arguments and arguments that are

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going to be passed on such restrictions on cardless preconditions.

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And in order to enforce such preconditions we can do some parameter validation at the beginning of the

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matter.

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OK.

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So let's also do that let's also enforce a precondition in cyber if statement here at the beginning

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of the matter and destination value is either less than zero or greater than one.

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Let's throw an illegal argument exception

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and this one is from the July-August Lang package and since it's an unchecked exception you can see

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that there is no compulsion at all here.

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So we need not to specify it here but if we want to we can do that.

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And similarly there is no compulsion at all here.

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In fact here we have polymorphic types so let's remove that because they will catch that exception.

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So now we have only two exceptions here and there is no legal argument exception here just fine because

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it's an unchecked exception so owners just go ahead and document this particular exception because the

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Klan's hopla know about it.

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So will say it throws

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so this exhibition will be generated every destination is less than zero.

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Our destination is greater than one.

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So anybody in this method will have to look at this API and they can see that if they pass this kind

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of a value then it could be considered illegal and an exception will be genitor head knowledge just

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as umed duck here.

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The programmer was careless and he did not read the API documentation.

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Unsensible you off minus one Sananda just go ahead and exude your does.

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And as you can see an illegal argument exception has been generated.

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OK.

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So that's an unchecked exception.

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And generally we should run out such exceptions because they are programming flaws.

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And it's not good to catch them so that's about it and that's it.

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I'm off on two exceptions.

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Thank you.

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Happy coding.