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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

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
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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