#84 try with resources in Java

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In this lecture we are discussing about try with resources:
-- first question in mind is what is try with resources
-- answer to close the resource
-- ok, second question - can we close resources without try with resource
-- then, we come to use try with resources

#1 use of try with finally without catch (it is possible to use try with finally without catch)
-- try statement can be used along with the finally clause to ensure that a resource is properly closed or released,
regardless of whether an exception is thrown or not.

BufferedReader br = null;
try {
// create a new BufferedReader to read from the InputStreamReader
br = new BufferedReader(isr);

// read a line of text from the BufferedReader

}
finally{
if(br!=null)
}
Note : finally always execute either exception occured or not so that it is used to close the resources.

#2
try with resource
try-with-resources statement, we can simplify this code and avoid the need for a finally block:

e.g
BufferedReader br = null;
// read a line of text from the BufferedReader

}
catch(IOException e){
// write code that you need
}

}

Important: this portion are not in the video, it is for those who are curious to learn more about exception handling
#3 try with with multiple resource
-- In Java, you can use the try-with-resources statement to close multiple resources automatically.
The try-with-resources statement is a feature introduced in Java 7 that allows you to declare resources
within a try block and ensure that they are closed automatically when the block is exited, whether normally
or due to an exception.

e.g
try (Resource1 res1 = new Resource1();
Resource2 res2 = new Resource2()) {
// code that uses the resources
} catch (Exception e) {
// exception handling code
}

-- Resource1 and Resource2 are classes that implement the AutoCloseable interface,
which allows them to be used in the try-with-resources statement.

-- The code within the try block uses these resources, and they are automatically closed when the block is exited,
either normally or due to an exception. If an exception is thrown, the catch block can handle it as necessary.

-- Resource1 and Resource2 are declared and instantiated within the try-with-resources statement. If the resources are
already instantiated before the try block, we can simply pass them as arguments to the statement.

-- the resources are closed automatically when the try block is exited,
and there's no need to explicitly call their close() methods.

In multiple statement inside try, order of closing resources:
-- Resources declared within a try-with-resources statement are closed in
the reverse order of their declaration, from right to left.

-- Resource1 is declared first, followed by Resource2, and then Resource3.
When the try block is exited, the resources will be closed in the following order:

Resource3
Resource2
Resource1

-- order is reversed from the order of declaration, with the resource declared last (Resource3) being closed first,
and the resource declared first (Resource1) being closed last.

Important:
It's important to note that the order of resource declaration matters when using try-with-resources,
especially if the resources are dependent on each other. For example, if Resource2 depends on Resource1 and
Resource3 depends on both Resource1 and Resource2, then they should be declared in the correct order to avoid any
potential issues during closing.

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[syedadil]

Is this playlist enough to learn spring boot?

[anveshi]

if we also have an exception in finally block
then what will happen🤔🤔

[sutapapaul]

Since you are an expert here, and I am not getting answer... How do we handle this--> I am going to create and use two resources in try block. But second resource is created from first resource. Just a structure,
Resource rs1= something
rs1. Something ()
Resource rs2=rs1.somethingelse()

Can we have this in 1 try with resource without nesting it?