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Note: In a call to a static method, the name of the class in which it is defined can be given as in the second call.Since the method is defined in the same class as the call, the class name need not be given, as shown in the first call.

Exercise Trace the execution of a call of the following method and explain why it doesn't swap the values of the actual parameters.

void swap(int a, int b) {  int temp = a; a = b;  b = temp;}

Can you write a method to swap two integer values?

A method returning a value

Concept When a method that is declared with a return type is called, it allocates memory for its parameters and local variables, executesits statements and then returns a value of the type. The call is a statement constructedfrom the name of the method followed by a list of actual parameters; the call is an expression and can appear wherever an expression is allowed.

Program: Method02.java

// Learning Object Method02 //    methods returning a valuepublic class Method02 {     static int maximum(int a, int b) {        if (a > b)             return a;        else             return b;    }      public static void main(/*String[] args*/) {        int x = 10, y = 20;         int max;        max = maximum(x, y);         System.out.println(max);    } }
  • The variables x and y are allocated and initialized; the variable max is allocated but not initialized.
  • An assignment statement is executed: the expression on the right hand side is a method call including the values of the actual parameters x and y .
  • Memory is allocated for the formal parameters of the method and the local variables. This is called an activation record and is displayed by Jeliot in the upper left hand part of the screen labeled Method Area . The new activation record hides the previous ones which are no longer accessible.
  • The actual parameters are used to initialize the formal parameters in the activation record.
  • The statements of the method are executed.
  • When the statement return b is executed, the value of b is used for the value to be returned.
  • The method returns and the activation record is deallocated.
  • The value returned becomes the value of the expression assigned to the variable max .
  • The value of max is printed.

Exercise Write the body of the main method as one statement.

Calling one method from another

Concept One method can call another, that is, when executing one method, any statement or expression call be a method call. A sequenceof method calls results in a stack of activation records, where each method (except the last one that was called)is waiting for the method it called to return. There is no limit on the depth of method calls, except of course the amount of memory allocated to the program.

Note: The main method is a method like any other. The operating system can be considered as a program which calls the main method.This call has a single parameter: an array of strings containing the contents of the command line.

Program: Method03.java

// Learning Object Method03 //    calling a method from a methodpublic class Method03 {     static int maximum(int a, int b) {        if (a > b)             return a;        else             return b;    }      static void printMax(int a, int b) {         int max;        max = Method03.maximum(a, b);         System.out.println(max);    }      public static void main(/*String[] args*/) {        printMax(10, 20);     }}

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Learning objects for java (with jeliot). OpenStax CNX. Dec 28, 2009 Download for free at http://cnx.org/content/col10915/1.2
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