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This is illustrated in the following code fragment. This fragment also illustrates the use of the length method of the String class just to make things interesting. (A simple integer value for the capacity of the StringBuffer object would have worked just as well.)

Instantiating a StringBuffer object of a non-default length StringBuffer str6 = new StringBuffer( "StringBuffer named str6".length());str6.append("StringBuffer named str6");

Accessor methods

The following quotation is taken directly from The Java Tutorial by Campione and Walrath.

"An object's instance variables are encapsulated within the object, hidden inside, safe from inspection or manipulation by otherobjects. With certain well-defined exceptions, the object's methods are the only means by which other objects can inspect or alter an object's instancevariables. Encapsulation of an object's data protects the object from corruption by other objects and conceals an object's implementation details from outsiders.This encapsulation of data behind an object's methods is one of the cornerstones of object-oriented programming."

The above statement lays out an important consideration in good object-oriented programming.

The methods used to obtain information about an object are often referred to as accessor methods .

Constructors and methods of the string class

I told you in an earlier section that the StringBuffer class provides a large number of overloaded constructors and methods. The same holdstrue for the String class.

Once again, I will refer you to Java OOP: Java Documentation where you will find a link to online Java documentation. Among other things, the documentation provides a list of theoverloaded constructors and methods for the String class

String objects encapsulate data

The characters in a String object are not directly available to other objects. However, as you can see from the documentation, there are a large number of methodsthat can be used to access and manipulate those characters. For example, in anearlier sample program ( Listing 2 ) , I used the length method to access the number of characters stored in a String object as shown in the following code fragment.

StringBuffer str6 = new StringBuffer( "StringBuffer named str6".length());

In this case, I applied the length method to a literal string, but it can be applied to any valid representation of an object of type String .

I then passed the value returned by the length method to the constructor for a StringBuffer object.

As you can determine by examining the argument lists for the various methods of the String class,

  • some methods return data stored in the string while
  • other methods return information about that data.

For example, the length method returns information about the data stored in the String object.

Methods such as charAt and substring return portions of the actual data.

Methods such toUpperCase can be thought of as returning the data, but returning it in a different format.

Creating string objects without calling the constructor

Methods in other classes and objects may create String objects without an explicit call to the constructor by the programmer. For example the toString method of the Float class receives a float value as an incoming parameter and returns a reference to a String object that represents the float argument.

Questions & Answers

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
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
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
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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