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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

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, 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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