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(A method that is declared static is commonly referred to as a class method. If the method is not declared public , it may not be accessible from your code.)

Accessing the static method

This is illustrated by the following fragment from the program, with much of the code deleted for brevity.

//... Worker.staticMethod();//... class Worker{public static void staticMethod(){ //...}//end staticMethod()}// end class

The class named Worker defines a public static method named staticMethod . A statement in the main method of the controlling class calls the method by referring to the name of theclass and the name of the method joined by a period.

When should you use static methods?

Static methods are very useful as utility methods (getting the absolute value of a number, for example) .

In my opinion, you should almost never use a static method in any circumstance that requires the storage and use of data from one call ofthe method to the next. In other words, a static method may be appropriate for use when it performs a specific task that is completed each timeit is called without the requirement for data to persist between calls.

The Math class contains many good examples of the use of static methods, such as abs , acos , asin , etc.

Back to Question 7

Answer 6

D. 3.1415927

Explanation 6

Using a public static final member variable

The class named Worker declares and initializes a member variable named fPi .


Because it is declared final , it is not possible to write code that will change its value after it has been initialized.


Because it is declared static , it can be accessed without a requirement to instantiate an object of the Worker class. All that is necessary to access the variable is to refer to the name of the classand the name of the variable joined by a period.

Because it is static , it can also be accessed by static methods.


Because it is declared public , it can be accessed by any code in any method in any object that can locate the class.

Type float is less precise than type double

Because the initialized value is cast from the type double that is returned by Math.PI to type float , an 8-digit approximation is stored in the variable named fPi .

The double value returned by Math.PI is 3.141592653589793

The cast to type float reduces the precision down to 3.1415927

Back to Question 6

Answer 5

C. 5

Explanation 5

Using a final local variable

Well, I finally got rid of all the bugs. This program uses a final local variable properly. The program compiles and executes without any problems.

Back to Question 5

Answer 4

A. Compiler Error

Explanation 4

The purpose of this question is to see if you are still awake.

What caused the compiler error?

The statement that caused the compiler error in this program is shown below. Now that you know that there was a compiler error, and you know which statementcaused it, do you know what caused it?

public final int x = 5;

Using public static final member variables

As I mentioned in an earlier question, the final keyword can be applied either to local variables or to member variables. When applying the final keyword to member variables, it is common practice to declare them to be both public and static in order to make them as accessible as possible. For example, the math class has a final variable that is described as follows:

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
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s. Reply
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are you nano engineer ?
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s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
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s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
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this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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