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Not look at a statement called Try with resources which was introduced in July 7 as the name suggests

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it has something to do with the try block and also get resources or resources could be classes to present

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something like operating system resources like file handles which has been performing.

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I would look at operations like reading from a file on the main thing the statement does is to automatically

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close such resources.

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So let's go ahead and learn about it.

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It is very straightforward.

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At the end of the lesson people will also be a short demo of what we like and their demo.

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We would also look at something called suppressed exceptions to understand the benefit of the right

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with resources.

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First let's look at an example here is the standard template which was used before jealous event for

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reading it offered him a data hitting the block.

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Are creating a file input stream instance which acts as a resource for reading it offered him a fight

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the code for reading the dies on the dead as it is not relevant for this discussion.

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There is also a catch block for handling file not one exception that can be drawn by the construction

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of the file input stream class.

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We also have the finally block with the file input stream instance is closed so that the system resources

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that it uses on at least this way there will not be any resource leaks.

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We already know the finally block will always be executed.

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No no it is the finally block.

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How one mark like I should talk and that's because the Ruelas method can do an Iowa exception.

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Moreover we are also checking that the reference to the above in is not enough.

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And if it is not not only then we close the input stream not that available and can be none if the file

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input stream object would not be created.

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That is a fine enough one exception was generated when we were trying to create dump file input stream

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object.

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So that this check could get a null pointer exception when the Close method is invoked.

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Now as you can see this whole finally block it looks very ugly with the cross try catch block and the

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additional check and also the up close method and location.

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So I want this we have the quite with resources statement which was introduced in Java 7 and it is the

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same code but with that drive with resources statement as you can see it looks much cleaner.

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The ugly looking finally block and we have only to try and catch Brocks here the resources are created

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Witan the parenthesis that follows the tricky word.

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So the declaration is also done within the parenthesis and it will not work if declaration is done outside

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of the parenthesis and initialization is done within the parenthesis in the old syntax declaration was

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done outside the block.

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So a try with resource is the cleanup operation is taken care of implicitly.

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That is a close method is in work implicitly after the block is executed.

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In reality the compiler inserts the and finally block into the bytecode.

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So even if an exception is generated the Close method is still invoked.

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Just as in the case of using a finally block explicitly you're also catching an exception as we know

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that the Lewis-Smith there which is invoked implicitly can throw an exception just know that the resource

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created in the parenthesis is implicitly final so it cannot be reassigned within the try block.

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Unsisterly sources are being automatically closed.

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This particular feature is also referred to as Automattic resource management or for short.

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Here is another example that might deploy resources are being created within the type but and this is

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they are created from left Left-Right right.

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That resource creation expressions must be operated by semi-colons in disguise syntax wise.

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It looks a bit similar to fuddle Not that once the block is completed resources will be closed in the

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reverse order.

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That is a file output stream instance is close before filing puts team instance even if there was a

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failure in creating one of the resources then the resources created so far which are on its left will

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be crossed.

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And here is a general syntax.

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Any resource that we create in the parenthesis must be off by auto plausible which is an interface in

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the Jawa line package.

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It means that the class of the resource hostile implement Article interface or one of its subintervals

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us or disclosable has only one method which is a closed minded support filing stream on file output

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stream classes implement articles about not do the try block need not have a catch block if the occludes

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method which you implement as part of implementing articles aboon does not throw an exception.

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And of course the code of conduct by block should also not to an exception.

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So a cry with the social statement need not how either to catch Quarter-Finals block.

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But if you want to you can have an explicit finally block that would perform something other than the

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cleanup operation Sooke trying with resources would come into play only when dealing with autoclaves

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or build resources and hence it is called aspart private sources.

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If you're not dealing with all the possible resources then you will have to use the regular old fashioned

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type block which does not help but analysis and here are some subtypes of our disclosable on the left

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.

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We have usable interface which is from the Jawa I will package most of the classes implement this interface

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even classes like socket arm scanner which are from other packages implemented.

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And we also have the interface of resultset which is from the package job X doc askew and it also extends

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our doc Rosabel.

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Similarly we can also see that there is a line interface from one of the packages from the sound API

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and it also extends our global.

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So all of these can be used in the parenthesis.

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I would also recommend taking a look at the articles about interface in the J.Y..

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So thats a try with resources.

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It is mainly used to automatically growth resources unexplored cleanups and backs down using finally

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for growing resources.

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No look not to pull up my editor you assured them off with resources OK for this demo.

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We have this new class called us try with resources gimel and it is added to the exceptions package

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and it has only one method File.

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Copy that I'm being on stands for automatic resource management it with an Iowa exception and this method

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doesn't work from the main method.

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And since it throws an exception we are also catching it here now as the name suggests this method is

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doing a file copy which means that it is reading the contents of a file and writing those contents for

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a different destination.

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And that's being done here.

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So here we have the private resources index and we are declaring pool resources.

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Resources are being created here.

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One is a buffered input stream instance and the second resource is a buffered output stream instance

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.

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So input stream instance is used for reading or stream instance for writing.

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Again that's not worry about the code for reading and writing on the Phylis basically a big file here

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and they put me as violent or jpeg output would be this.

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So here it is valid in Georgia.

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So let me just go ahead and run this.

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Here does not let me refresh this.

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So as you can see the file got created here and here the resources are also separated by a semicolon

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.

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Now let's try a bunch of things that we discussed on this.

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I mean just take this.

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Now as you can see we're getting a compilation error here and that's because the resource has to be

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created within the parenthesis.

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It cannot be created outside and we cannot initialize it here.

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That cannot be done.

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As we discussed in the in the lesson so that cannot be done.

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So let me just bring it back here and one other thing we discussed was that we cannot re-initialize

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a resource variable here so we cannot do this.

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And that's because we said that in here is implicitly final and final cannot be reassigned.

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So we know that.

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So that's why this is not possible and hence we can see a compilation error.

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So let me just delete this also.

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And the next one is.

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So here you are trying to create a string instance and it will give a compilation error.

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And that's because string is not a resource which means that it does not implement auto Clozaril interface

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with the close method.

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So that's not possible.

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Anything that goes here has to be a resource which implements or disclosable.

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Now those are the main things that were discussed in the lesson.

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So one thing with which we did not discuss was suppressed exceptions.

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And let's look at that now.

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So for this let me just copy this here and paste it here.

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So these are two instances So basically those are two resources.

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One is an instance of class Test.

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On the other is an instance of Desta.

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And those are defined here at the bottom of this white.

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So outside of the tribe with resources class we are defining these two classes.

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One is d'Este which implements hardcores a bill and also the Glos method and the close method is throwing

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an Iowa exception.

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The actual close method in order goes is an exception.

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But here we are generating an exception under.

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It also recommends that we need to to aspecific exception as possible and in case of the close mentor

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is not ruling any exception then we can avoid doing any exception here.

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We don't need to how it goes across here.

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OK.

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So if it is not required.

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That's not how it throws across here but it does require quite to keep it as specific as possible.

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And this exception this method of throwing exception.

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But the message will be an exception on test results implementing or disclosable the Close method.

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And it is throwing that exception with the message to be an exceptions based too.

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And that's because that it's named us Desta.

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OK so the only difference is two as being carded here in the message also.

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So that's what we hope.

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And here let me come on Das also.

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So in this case.

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So in the right block we are throwing an exception.

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So after doing the copy here we are throwing this exception at the very end.

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OK.

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So let me just go ahead on her on this.

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Come on.

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So it will throw exceptions and as you can see so you can see the exception.

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So the first the main exception that is being generated is this exception Iowa exception that's maybe

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how this exception is getting printed here.

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And here is the stockers that you're catching that exception and we are doing it.

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No didn't.

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The important exception we can see that that is this suppresive exception and that is the second supplement

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exception.

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So those are generated here.

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So once this dry block is executed we know that the resources are closed in the reverse order.

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So first it will be closed then it will be closed and will be closed on Wednesday is closed.

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The exception.

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So that's the real exception.

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And that will be encapsulated inside this Aiwa exception as a suppressed exception.

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And then after that even DVM tries to close this and also throws an exception and that exception is

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the trivial exception that is also and gaps embedded within Aiwa exception has a suppressed exception

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.

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So we have these exceptions here and it is a nice big it's a nice way to do it because here we are calling

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it as an important exception because normally you how only one an exception generated here in the try

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block is more important because it will have some important details.

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I bought something significant must have happened here.

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But what it has when it comes to of exceptions those are those are generated by the rules meant there

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is normally you know an exception is non-gendered macros matter.

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So it would be something not that important or competitively it will not be as important as the exception

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generated from the from within that block.

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So that's why it is suppressed.

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So I think that's up to.

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The exception is not that important exception.

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Now here is the abstract trace but I guess if you if the developer or whoever is invoking the client

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who is invoking this matter wants to extract the suppressed exceptions then they can do it this way

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.

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So let me just comment this uncommon this court.

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So here we are watching the important exception and we in looking him at their court gets suppressed

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which is from the to overlook Iron Age credenza on off two of his circuit and an army officer present

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exceptions.

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OK.

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So so this is added in July 7 just like try with resources Sendak's which was also ordered in Dallas

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.

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So this is an army that will have two exceptions up as exceptions.

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And we are counting on a spending message this year.

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So if we are on it.

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So we have this so important exception as the main exception under somewhat some exceptions are trivial

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exceptions.

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Now if this is what the trial would send back to I with resources Sendak's.

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But if we just use and not try catch finally block and if we have the same thing happening the resources

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throwing exceptions when will that blows matter.

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And if you also have this kind of an important exception then the exception that could be determined

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by this matter would be one of these the exceptions that are generated from the finally block.

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Just recall that in the regular old fashioned try block the Close method to be invoked in the finally

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block.

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So that gives only the one of the first Groos method were through an exception undocked would be going

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by this method on the second exception thrown by the second method and also the important exception

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will be ignored.

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And that gives the caller just masked masked Dix's exception and you can fix the Massena exception by

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making it a suppressed exception.

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We need to write some additional code for that.

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And that's what even the with resources index is doing internally and we can do that to fix the mast

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exception problem they ignored exception rubbed up on what we've been seeing the in the next lesson

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.

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So that's about it for now.

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Thank you.

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And happy coding.

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And you can also find discord in the resources section.

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Thank you