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Jaw Why is referred to as it type safe language.

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And in this lesson we'll see what that means.

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The reason we are not looking at this concept of type safety is because it is relevant to what we saw

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in casting objects specifically.

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We encounter a few compile time and runtime errors on those are due to the result of applying typesafe

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needles.

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So let's go ahead and see what biosafety means.

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According to Wikipedia bike safety is the extent to which a programming language prevents something

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called pipefitters.

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So let's see what bipedally means.

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Type errors are certain bot kind of errors that could lead to undesirable program behavior.

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Let's look at a couple of examples.

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One example could be in Wilkin nonexisting method on an object in our history.

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The class stuff does not include a Proview mattered.

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So we should not be able to invoke this method on a staff object.

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We already know that Java's compiler will not allow us to do this but some languages that are not safe

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could allow this and it could lead to some undesirable behavior.

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Second example is related to memory safety on one specific example is buffer overflow which is usually

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associated with languages like C and C++.

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Let's consider this example declaration in C language where a catenary is initialized with the string

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hello and this will get co-presenter in memory as shown here after hello.

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We have a null character indicating that I need a string after null character in the adjacent memory

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location.

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We have some data from some other variable and this gives the character a non Nazi.

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We want to insert the katak to be in the very next position 6.

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However it would be invalid as it is outside the RSA range but in a pipe unsafe language this could

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override that data in the next memory location.

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So you can see that he has got over it done with chiropody.

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So basically what happened was data got corrupted undocks an undesirable behavior.

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So these are kind of pipe errors that are typesafe language.

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We're trying to avoid some languages trying to put two in pipefitters at compile time.

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Some do it only a runtime while some others do that but compile time and run time and what does it both

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compile time as well as runtime types if checks that are done at compile time is also referred to as

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a static type checking one of checks done at runtime.

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Is your footrests dynamic like chicken.

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C and Pascal are examples of languages that use only static type checking.

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While Ruby and Python are examples of languages that use only dynamic electrican not let's look at couple

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of stocktake by picking examples in Java.

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We know that in Java they get a compiler error when we do this.

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That is we cannot assign a larger type with a smaller type.

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So here we are trying to assign a double literal to an incredible and we also know that the solution

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for this is to insert an explicit cast and we also know that we cannot work on non-existing matter here

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the reference type stuff does not include the proof review method on compiler promptly the parser solution

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once again is to insert an explicit cast.

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Finally genetics is all about types of beat at compile time.

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Before generics many of the errors were only caught at runtime but with the introduction of generics

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and Jollof I knew many of those errors at compile time access.

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And that is what is before.

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You would want to detect as many errors as possible at compile time itself.

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So when we get to generics you will see me using the phrase type safety.

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Quite a big Nona's checkout to a couple of examples on how GBM uses dynamic type checking to prevent

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some of the pipe errors.

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We saw this example when discussing object winds are going to cost promising the compiler that variable

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S will always reference either an editor object or one of its subtypes but render the method with a

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stop object.

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We get a runtime error art class class exception indicating that the Stav object could not be Castner

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to Ed..

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We know that this is because stuff can be an editor but it can also be something else like an email

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address.

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So people who enter type for JVM destroying this runtime error thus avoiding any undesirable behavior

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.

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And this example demonstrates prevention of buffer overflow type error here Qaderi is first initialized

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with the characters hello and then we are trying to access element index location file which is altered

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off I responded.

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So the get runtime error card again.

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This sort of bonnes exception as you can see the name of the error does the story so we can see the

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dynamic by checking Crozon in order to avoid any undesirable behavior.

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Basically Java static budgeting is enforced to prevent as many type errors as possible at compile time

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itself.

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However it is impossible to prevent all of that by bettors only at compile time.

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So the ones that cannot be prevented at compile time are they can get off at runtime using dynamic type

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checking.

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So John Law uses both static and dynamic type checking and response doesn't typesafe language.

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Also note that since toxically type languages do all the chicks at compile time itself and do not need

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any additional checks at runtime they can still be faster than dynamically typed languages which have

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to do all of the checks at runtime.

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No sometimes people incorrectly use terms like strongly typed system to refer to static typing on Veeck

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type system to refer to dynamic typing.

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Unfortunately there is no standard definition for strong or weak type systems.

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But let's look at some acceptable views for these two items.

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Strong typing generally means that there are no loopholes in that type system.

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That is a pipe system of a language gives certain guarantees.

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If the language is strongly typed.

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You cannot go out and undo something but in reality it does not and is on the other hand Veeck typing

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means that the type system has some loopholes and hence can be subverted.

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Invalidating any guarantees and in this respect July is considered as a strongly typed language.

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Some experts say that C is a Beagley type language as it seems to have several loopholes so that support

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type safety on July is considered as a type safe language.

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It is very strict about type safety and uses both static and dynamic typing.

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I'm also including some relevant pointers in the supplementary notes.

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If you're interested you can check them out.

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Thank you