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We are not done with the language basic series.

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And with that we have set a solid foundation towards mastering Djala.

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We mastered all the essentials in the process.

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We also learned about Ben Arcel effective July dance.

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Next we will learn more serious object oriented programming and concepts like inheritance polymorphism

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abstract classes and interfaces that we will how all the tools to write some awesome object oriented

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programs.

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Let's not look at some of the topics we covered in this chapter.

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We started with startlement the 10 variables we next looked at final variables within a box primitives

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an auto boxing.

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Finally we did several coding conventions.

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So let's go ahead and look at some of the important points we covered in this chapter.

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First a static method.

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Static methods are simply class methods.

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Are basically utility methods that do not depend on state.

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That is the instance variables are an instance methods they can access only static syllables and other

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static matters.

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If your class has only static methods then you can make the class non intangible by marking its concept

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class by weight.

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Next we'll discuss tactic was ecstatic methodes stopped equatable class variables that is shared across

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different objects of ductus.

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So there are not an instance variables which are unique to each object and with regards to accessibility

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they're accessible from static methods but they're also shared across objects of the class which means

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that they're also accessible from instance methods as well as constructors Mexoryl is because finally

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variables the term final simply implies that something cannot be changed.

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That is it is final.

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So if a variables value should be final that is it shouldn't change once initialized then it needs to

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be my best final So finally reliable.

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Basically in place constant if it is used with a primitive variable then the value can never be changed

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.

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But recall that if it is used with reference variable then the reference is constant.

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That is a reference all response to the object initialized it and cannot be reassigned another object

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Hello contents of that object can be changed.

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So you should keep that in mind.

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Find out what it was.

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Do not get a default value.

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And the reason for that is a final variable gets a default value and is initialized once again.

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Let's say in a constructor then we are violating its coater definition on final keyword can be used

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with any of the three kinds of variables.

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That is instance local are started as part of final variables.

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We also discussed about constant variables which are a kind of final variables whose values are known

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at compile time itself.

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For this reason they're usually also referred to as compile time constants.

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And here is an example which is a variable Pi from the math class.

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Compile time constants below compilers to perform some optimization.

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For example here we have variable x which is assigned my doc by.

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But my point is a compile time constant and the compiler knows the corresponding value 3.1 for citizens

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3.1 for directly to the variable x unstarted in the class file as part of the bytecode.

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So this element of some overhead at runtime as JVM doesn't have to look into math class to make this

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assignment.

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So compiler is able to perform such an optimization and here are some restrictions for a final really

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.

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But to be qualified as a constant variable first is obviously it needs to be declared with the modifier

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final.

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Next a deadlock type of variable should be either a pyramidal or a string.

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If you have any other data type then it will not be a constant variable.

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So that's a very important point to remember.

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Next variable must be initialized in the declaration statement itself.

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That is it cannot be initialized somewhere else like in a constructor or in some initializer block.

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Finally the initialization expression itself must be a constant expression a constant expression is

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something whose value is known at compile time itself and hence it is also referred to as compile time

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constant expression.

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There are some rules on what expressions qualify as constant expressions but typically you would see

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either put them a Dolittle's or string literals as constant expressions like in the case of mad dark

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by next that box primitives and then a related topic called auto boxing auto boxing which was introduced

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in Jollof I blurred the distinction between put him into Dave's unboxed promotors for example baulks

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primitives could be directly assigned primitives on similarly primitives could be directly assigned

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baulks primitives.

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Also the art of boxing images could be directly added good data structures like orderless and this.

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How about introducing what city hall or one of the effect of their lifetimes.

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Cautions that there are some issues that we met on indu.

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If box primitives are used carelessly we discuss the issues and how also tried them out in gold.

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Finally we look at coding conventions which are critical for writing clean and professional good.

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The first look that naming conventions onwards goes pretty much all the recommendations that are suggested

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by I am 56 mid-strength on sticking to generally accepted naming conventions rediscuss but typographical

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ungrammatical naming recommendations on Risher try to follow them as much as we can.

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Next we'll have the conventions for how to structure our programs.

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We said when designing our classes they should follow the single responsibility principle which simply

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means that the class should have only one responsibility.

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This would also limit the class size and more importantly would help us create better abstractions.

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That is how loosley couple classes next with regards to amateurs.

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We should try to keep them very small unfocussed they should do only one thing no more.

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We are told that one recommendation from Effective Java whose suggestion was to minimize the scope of

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local variables.

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The item recommenced or declare a local library but there it is fussiest.

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It also recommends to use for loops and sort of bli loaves as frontal lobes are better at minimizing

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the scope of variables and help in preventing bucks.

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Finally we look at some conventions for writing comments generally common should provide overuse of

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code.

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It is perfectly fine to describe any non-obvious design decisions but do white writing frequent comments

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under-fire being compelled to write frequent comments.

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Then it means you may want to consider the factoring some of the stuff usually just good descriptive

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method and variable names undoctored so of us documentation.

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And that's about it.

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We have set all the necessary foundations that we need and we can no more want a more advanced off.

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Thanks for listening and I will see you in the next chapter