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What is Abstraction in OOP?Abstraction is the concept of object-oriented programming that “shows” only essential attributes and “hides” unnecessary information. The main purpose of abstraction is hiding the unnecessary details from the users. Abstraction is selecting data from a larger pool to show only relevant details of the object to the user. It helps in reducing programming complexity and efforts. It is one of the most important concepts of OOPs.
Let’s Study Abstraction in OOPs with example:Suppose you want to create a banking application and you are asked to collect all the information about your customer. There are chances that you will come up with following information about the customer
Abstraction in Java
So, you need to select only the useful information for your banking application from that pool. Data like name, address, tax information, etc. make sense for a banking application which is an Abstraction example in OOPs
Since we have fetched/removed/selected the customer information from a larger pool, the process is referred as Abstraction in OOPs.
Difference between Abstraction and EncapsulationAbstraction Encapsulation
Abstraction in Object Oriented Programming solves the issues at the design level. Encapsulation solves it implementation level.
Abstraction in Programming is about hiding unwanted details while showing most essential information. Encapsulation means binding the code and data into a single unit.
Data Abstraction in Java allows focussing on what the information object must contain Encapsulation means hiding the internal details or mechanics of how an object does something for security reasons.
Difference between Abstract Class and InterfaceAbstract Class Interface
An abstract class can have both abstract and non-abstract methods. The interface can have only abstract methods.
It does not support multiple inheritances. It supports multiple inheritances.
It can provide the implementation of the interface. It can not provide the implementation of the abstract class.
An abstract class can have protected and abstract public methods. An interface can have only have public abstract methods.
An abstract class can have final, static, or static final variable with any access specifier. The interface can only have a public static final variable.
What is Abstract Class?Abstract Class is a type of class in OOPs, that declare one or more abstract methods. These classes can have abstract methods as well as concrete methods. A normal class cannot have abstract methods. An abstract class is a class that contains at least one abstract method.
What are Abstract Methods?Abstract Method is a method that has just the method definition but does not contain implementation. A method without a body is known as an Abstract Method. It must be declared in an abstract class. The abstract method will never be final because the abstract class must implement all the abstract methods.
Advantages of Abstraction
The main benefit of using an Abstraction in Programming is that it allows you to group several related classes as siblings.
Abstraction in Object Oriented Programming helps to reduce the complexity of the design and implementation process of software.
When to use Abstract Methods & Abstract Class?Abstract methods are mostly declared where two or more subclasses are also doing the same thing in different ways through different implementations. It also extends the same Abstract class and offers different implementations of the abstract methods.
Abstract classes help to describe generic types of behaviors and object-oriented programming class hierarchy. It also describes subclasses to offer implementation details of the abstract class.
Summary:
Abstraction in Programming is the process of selecting important data sets for an Object in your software and leaving out the insignificant ones.
Once you have modeled your object using Data Abstraction in Java, the same set of data could be used in different applications.
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Encapsulation In Java Oops With Example
What is Encapsulation in Java?
Encapsulation in Java is a mechanism to wrap up variables(data) and methods(code) together as a single unit. It is the process of hiding information details and protecting data and behavior of the object. It is one of the four important OOP concepts. The encapsulate class is easy to test, so it is also better for unit testing.
In this tutorial, you will learn-
Learn Encapsulation with an ExampleTo understand what is encapsulation in detail consider the following bank account class with deposit and show balance methods
class Account { private int account_number; private int account_balance; public void show Data() { } public void deposit(int a) { if (a < 0) { } else account_balance = account_balance + a; } }Suppose a hacker managed to gain access to the code of your bank account. Now, he tries to deposit amount -100 into your account by two ways. Let see his first method or approach.
Approach 1: He tries to deposit an invalid amount (say -100) into your bank account by manipulating the code.
Now, the question is – Is that possible? Let investigate.
Usually, a variable in a class are set as “private” as shown below. It can only be accessed with the methods defined in the class. No other class or object can access them.
If a data member is private, it means it can only be accessed within the same class. No outside class can access private data member or variable of other class.
So in our case hacker cannot deposit amount -100 to your account.
Approach 2: Hacker’s first approach failed to deposit the amount. Next, he tries to do deposit a amount -100 by using “deposit” method.
But method implementation has a check for negative values. So the second approach also fails.
Thus, you never expose your data to an external party. Which makes your application secure.
The entire code can be thought of a capsule, and you can only communicate through the messages. Hence the name encapsulation.
Data Hiding in JavaData Hiding in Java is hiding the variables of a class from other classes. It can only be accessed through the method of their current class. It hides the implementation details from the users. But more than data hiding, it is meant for better management or grouping of related data.
To achieve a lesser degree of encapsulation in Java, you can use modifiers like “protected” or “public”. With encapsulation, developers can change one part of the code easily without affecting other.
Getter and Setter in JavaGetter and Setter in Java are two conventional methods used to retrieve and update values of a variable. They are mainly used to create, modify, delete and view the variable values. The setter method is used for updating values and the getter method is used for reading or retrieving the values. They are also known as an accessor and mutator.
The following code is an example of getter and setter methods:
class Account{ private int account_number; private int account_balance; public int getBalance() { return this.account_balance; } public void setNumber(int num) { this.account_number = num; } }Abstraction vs. Encapsulation
Often encapsulation is misunderstood with Abstraction. Lets study-
Encapsulation is more about “How” to achieve a functionality
Abstraction is more about “What” a class can do.
A simple example to understand this difference is a mobile phone. Where the complex logic in the circuit board is encapsulated in a touch screen, and the interface is provided to abstract it out.
Advantages of Encapsulation in Java
Encapsulation is binding the data with its related functionalities. Here functionalities mean “methods” and data means “variables”
So we keep variable and methods in one place. That place is “class.” Class is the base for encapsulation.
With Java Encapsulation, you can hide (restrict access) to critical data members in your code, which improves security
As we discussed earlier, if a data member is declared “private”, then it can only be accessed within the same class. No outside class can access data member (variable) of other class.
However, if you need to access these variables, you have to use public “getter” and “setter” methods.
What Is Public In Java?
Introduction to the public in Java
Web development, programming languages, Software testing & others
The syntax of public is shown below. In the below example, the variable word is declared as public inside the class Example. The variable word is available in the functions. The functions are Sum() and average(). So, the variable word is readily available in other functions, although it has not been specifically called in the respective function. In case of a variable that has been declared as private cannot be accessed in other functions or classes. Therefore, in the case where the variable is not allowed to get accessed in other functions, the access modifier private is used.
Code:
class Example { public int hello; public void sum(int a) { } public void average(int a) { } } Examples of public in JavaGiven below are the examples mentioned:
Example #1Now we see a coding example in which the public access modifier is used, and then it is used to add two numbers. There are two classes. One is the main() in which we create an object of Addition(), and then we call the other class through two numbers. The name of the object created is obj, and it is very useful in calculating the sum. There can also be other functions and classes such as Multiply as well as Divide. The coding example is a simple program where there are two classes.
Code:
class Addition { public int add(int a, int b){ return a+b; } } public class Main{ public static void main(String args[]){ Addition obj = new Addition(); System.out.println(obj.add(50, 50)); } }The two numbers which are included are 50 both. When we add the two numbers, we get the final output as 100, as shown. The function used to add the two numbers is add(), and an object is created. We can also create other classes where we can have other functionalities, and we can create that object in the main() of the program.
Example #2In this coding example, we create an object in the main(). The below program is used to multiply two numbers and produce the multiplication output. There is a single object obj that is created and is used to call two numbers. One is the number that has double as its type, which is used in the same class. In the Hello class, there is a main() which is created and is used to call the square() as well as the number which has its type as double.
class XYZ{ public double num = 100; public int square(int a){ return a*a; } } public class Hello{ public static void main(String args[]){ XYZ obj = new XYZ(); System.out.println(obj.num); System.out.println(obj.square(10)); } }Output:
The sample output is a clear depiction of the two variables, which are called inside the main(). First, the number 100, which has double as its type, is shown as well as the square of a number which is there in a function. There is a function square() which shows the square of a number and is created inside another class, and then inside another class, there is a main(), which calls the Square(), and the number is shown as input. The number which is shown as input, in this case, is 10, and the square of the respective number is 100, which is shown in the output panel.
Advantages of public in Java
Unlike the private access modifier, which is the most restricted modifier, public is used when functions are used to call in classes.
It is available in classes, package, subclass(within the same package) and subclass(within other packages).
Also, the functions are also available in other classes.
Public functionality is used for running programs which has a single main(), and there are multiple other functions that have different functionality, which is called inside the main().
ConclusionRecommended Articles
This is a guide to What is public in Java? Here we discuss the introduction to public in Java along with examples to implement public keyword in Java. You may also have a look at the following articles to learn more –
Is Diy Kitchen Crispr A Class Issue?
Growing up poor on a farm in Indiana, Josiah Zayner often felt like his dreams were out of reach. His family couldn’t afford to support his interest in computers, so he got a job at the local grocery store and saved money to buy his own modem. Being able to cultivate his passion for computers changed his life.
“I became inspired to do stuff like engineering and science, and was eventually able to go to graduate school,” says Zayner, a synthetic biologist who received his PhD in biochemistry at the University of Chicago and now runs his own biohacking supply company, called the Open Discovery Institute (ODIN).
In the excitement, Zayner raised more than $69,000, nearly seven times his original crowdfunding goal. He left his job researching bacteria intended for Mars terraforming at NASA to run the ODIN full-time.
Zayner’s efforts have been controversial. Though his CRISPR kits only provide supplies to perform very basic experiments, experts worry that Zayner’s kits could pave the way for more dangerous applications such as developing new pathogens. Others are concerned that people performing biology experiments at home might not properly observe lab safety protocols.
Zayner, however, is not entirely interested in operating within the already established DIYbio community, which he believes can be hierarchical and exclusive. The expectation that he should have the money and space for a dedicated fridge is classist, he says. “Who gets to determine what is safe?” he asks. “If you’ve been to a biohacker space, you’d know that it’s mostly white, upper-middle class people.”
“I want literally anybody to be able to do science—not just people who can afford a $100-a-month lab fee, or three fridges in a dedicated lab room in a 2,000 square-foot house,” he says.
The issue of basic safety is separate from class and racial considerations, says Tom Burkett, founder of BUGGS, a DIYbio lab in Baltimore. “It’s not white, middle-class people who are deciding what is or is not safe, it’s a larger community composed of biosafety experts,” he says. “Zayner is doing the DIYbio community a disservice by being cavalier about his safety practices. Not only could his example possibly get someone hurt, but it could also bring about increased regulation which would limit access to the technology.”
Zayner working in his home lab. Courtesy of Micah Zayner
For his part, Zayner says the bacteria (E. coli K-12) and yeast (S. cerevisiae) he uses are considered safe and exempt from the guidelines of the National Institute of Health, which issues rules for the labs that it funds. To him, these guidelines suggest that he should not need another fridge to separately contain his specimens.
It’s not necessarily realistic to impose lab-based regulations on home tinkerers, says Patrik D’haeseleer, co-founder of Counter Culture Labs, a DIY bio lab in Oakland, California. He thinks expanding the DIYbio community beyond established biohacker spaces will require some flexibility.
“Do we want to say that this kind of science should only ever be done in a formal laboratory setting?” he asks. “Or do we truly want to enable kids to do science at home?” If it’s the latter, then people will have to accept the fact that some experiments will happen in the kitchen, and it should be up to the makers of kits to make their experiments as safe as possible, says D’haeseleer.
However, D’haeseleer also thinks it’s possible to make DIYbio labs, such as Counter Culture Labs and BioCurious in Silicon Valley, diverse spaces. “In my personal experience, BioCurious and Counter Culture Labs are lab communities where I’ve seen the widest cross-section of society by far, in terms of age, gender, educational background, financial ability—you name it,” says D’haeseleer. “We try to keep our classes as free or low-cost as possible. We also have a sponsored membership application program where people can state however much they can afford to pay for membership.”
Whether it’s done at home or in a formal community lab, DIYbio is inherently a privileged activity, says Alondra Nelson, a professor of sociology at Columbia University. “On both sides it requires not only disposable income, but also leisure time to ponder and tinker.”
“In a world where, increasingly, working class people can’t get by on just one full-time job, hobbyist experimentation and biohacking are very much an upper-middle class exploit,” she says.
Discussions of DIY CRISPR point to larger questions of access, says Nelson, such as whether marginalized communities will have access to future health benefits made possible by the technique. “These are issues in which race and class are very much at the center,” she says.
“For all those times I saw an invisibility cloak that I couldn’t play around with, here’s a cutting-edge technology that I can play around with, and other people can play around with now,” he says.
Zayner’s CRISPR kits cost $140 for engineering antibiotic-resistant bacteria to survive on media they wouldn’t typically survive on, or $160 for engineering yeast to turn red as they grow. He sees his customers as people who want to explore science on their own, just as he taught himself to code in his parents’ house. “For me, it’s all about ‘how do we give those geniuses who are sitting in their moms’ basements access, so they can do brilliant things?’”
Victor Vran Review: Your Loot Is Your Class In This Addictive Diablo
You know what? I’m starting to think that the original Diablo III release being a terrible, horrible, no-good, very-bad game (or at least being perceived that way) was potentially the best thing that could’ve happened to the action-RPG genre.
I mean, it’s tragic that so many people felt they got screwed by Diablo III—and it’s great that Reaper of Souls eventually fixed most of the major issues.
But think about it: Before Diablo III, the action-RPG genre was largely stagnant. Then Diablo III came out, botched its launch, and people started looking around for something to sate those pesky aRPG cravings. From a dev perspective, suddenly Diablo III didn’t seem quite so unassailable. Torchlight blew up, Path of Exile launched, and the Van Helsing series nabbed some fans.
Let’s go ahead and add Victor Vran onto the list of genre classics while we’re at it.
Fifty ways to skin a monster“Something something I kill monsters because I am a monster hunter,” says titular character Geralt of Rivia Victor Vran (paraphrasing) and that’s about all the introduction you get in this game. And to be honest, it’s pretty much all you need.
I don’t know why a well-crafted aRPG is so addictive. If I had unlimited funding and knew a bunch of hard-up scientists, I might set them to studying the problem instead of finding a cure for cancer or whatever it is scientists do all day.
And you know what? It’s a fun time. Victor Vran isn’t revolutionary by any means—nor necessarily better than a mouse-focused game like Diablo. It does give Victor Vran its own identity though, which is important in an increasingly saturated market.
The game also ditches other aRPG trappings. For instance, remember how everyone was so excited about Path of Exile’s twisting, freeform skill tree? Victor Vran is the polar opposite. No “classes,” no “skill upgrades.” Instead, each weapon class comes with two unique skills. Enjoy fast, flashy kills? Try the rapier. Enjoy flying into the air and smashing the face off a wraith? Hammers.
Also, scythes. Because scythes are the most badass type of weapon, and always will be.
Leveling up gives you more health, more item slots, or more “Destiny Points.” Destiny Points/Cards are yet another method of customization—equipping them gives you bonuses to critical chance, health regeneration, et cetera.
Ugh, but this hat. Victor Vran belongs on /r/punchablefaces.
Victor Vran takes the loot game to its logical end, which is “Everything is loot. Literally everything you pick up is loot,” a.k.a. the Borderlands approach.
The upshot is you’ll swap gear more often than, say, Diablo. Since skills are tied to weapons, there’s a solid reason to keep around that shotgun or that hammer in your inventory, even if you only use it once every hour or two for specific boss enemies.
This modular approach to character classes also plays into Victor Vran’s other hook: Challenges. Each map is tricked out with five normal and five elite Challenges—everything from “Find six secrets” to “Slay fifty monsters within 120 seconds with a hammer.” They’re entirely optional, they’re pretty much entirely for bragging rights, and yet I can’t stop trying to finish them. I’ve restarted maps upwards of a dozen times just to complete some pointless Challenge.
I’m pretty sure Challenges are what’s keeping me hooked to Victor Vran, because it sure isn’t the story. I started writing an entire review of Victor Vran focused on the story, and quickly realized what a mistake that would be—because it really doesn’t matter. Diablo is a dumb game with dumb lore. Victor Vran is even dumber.
I do have some quibbles. For instance, each area is actually a massive hub and four or five smaller sub-levels. Not a problem. But for some reason the game re-hides the map and repopulates all the enemies in the hub world if you go back to the shop to sell anything or if you quit the game. I understand you don’t necessarily want a loot-based game to have levels devoid of enemies, but it led to me playing the game in a very specific way—completing all five Challenges on the hub world and discovering all sublevels, then accessing those sublevels from the level select screen instead of running back to them across the hub. It’s a bit of a cheat.
Also, I experienced some minor performance issues, even running on a GeForce GTX 980 Ti. Tons of particle effects on-screen would make the action lag and then jump ahead occasionally, and this game doesn’t look nearly good enough where that should occur, even on Ultra.
Bottom lineIt’s more than a bit silly and mindless but, well, the whole aRPG genre is a bit silly and mindless. Victor Vran strips out some of the complexity of its peers, but makes up for it with a dynamic combat system and incredibly modular character customization. And the most awful hats. And stale jokes that are so stale they’re almost funny again. Almost.
I ended up enjoying this one more than I expected. It’s not perfect by any means, nor would I say it’s as good as genre leaders Diablo, Path of Exile, and Torchlight. But it still kept me up until 4 A.M. one night, so I’m calling this a win.
Using Pbl In Environmental Science Class
A few years ago, my students became bothered by the number of plastic bags showing up in the Guyandotte River, which winds behind our school and through our rural southern West Virginia towns. They believed that recycling and other waste management options would decrease littering, but we didn’t know where to start—our rural county had no recycling program.
As an AmeriCorps alumna, I was familiar with launching community programs without a budget. By merging apprenticeships and project-based learning (PBL) in my environmental science class, we were able to create our county’s first recycling program.
The Setup
Our students initially started an after-school recycling program, which rapidly evolved into our county’s only recycling center within one year. We grew so quickly that we needed outside help, fast. PepsiCo Recycling Rally provides curriculum and equipment to jump-start recycling collection at your school, so we started to use those resources.
Merging PBL with the apprenticeship model provided a framework for designing units with learning outcomes that build critical thinking and creative problem-solving skills. Operating a recycling center does not work if our student body and community do not know our recycling procedures, what can be recycled, or how recycling can save our streams. Students share their knowledge by organizing schoolwide recycling pep rallies featuring recycling games they develop. They organize school assemblies and create videos, theatrical performances, and rap songs about recycling procedures.
To determine the effectiveness of our outreach programs within our school, we conduct waste audits, analyzing data to see the percentage of recyclables and trash in correct bins. My students design educational activities for local fairs and festivals, teaching students why it’s important to understand where our waste goes and how to best manage it. They work with our communities to assess microplastic levels along our riverbank and launched a Spotify podcast, Waste in Our Waters. They also create and deliver presentations to our town councils and county commission because our ultimate goal is to create a countywide recycling network.
Our program is unique because there are both curricular and extracurricular components. Plastic pollution and waste management are only two units in the environmental science curriculum, so it’s challenging to dedicate the time to complete all the tasks for running a recycling program and addressing plastic pollution within a classroom. If we don’t complete our weekly requirements of collecting and sorting recyclables during class, which happens frequently due to teaching other content standards, then the after-school program picks up the slack. It takes seven to 10 students to stay on top of the recycling demands.
Transforming students into environmental leaders does not happen overnight. It requires time and intentional planning, but the outcomes are what we hope for as teachers: confident, engaged, and civically minded students.
Growing Student Environmental Leaders
Here are eight steps for creating environmental change makers. Although some of these features are standard in PBL, there is much more of an emphasis on building community relationships when using the apprenticeship model.
Make observations: Instruct students to record observations about the environment while walking around campus. Are there invasive species, sources of pollution, or suitable habitats for specific species?
Find patterns: Discuss patterns that emerge from your students’ observations. Record these ideas, and let students prioritize topics.
Identify community experts: Specialists may be found at museums, parks, and/or natural resource and environmental agencies. National Geographic’s Explorer Classroom and Exploring by the Seat of Your Pants YouTube channels connect classrooms to experts across the globe. The expert’s role is to extend the students’ background knowledge about the selected environmental issue. Ask students how they felt and what interested them after a session with an expert. Are there additional questions or ideas for solving their environmental issue?
Determine the environmental project: Tell students that local problems are often global problems, and instruct them to research ways that other organizations, states, and countries solve related environmental problems. Ask students to share what they learned. Are there feasible projects for the students to modify or replicate? Is there a stand-out project that clearly fits your students’ interests?
Identify stakeholders: Instruct students to brainstorm individuals and organizations in your community that have a vested interest in helping fix this environmental problem. Reach out to these stakeholders for help.
Create a step-by-step plan: Guide students through enumerating all actions required to complete their project. What materials do they need? What is the time frame for completing the project? Who can complete each task? Allow students to express their interests and self-select tasks.
Work alongside community mentors: While meeting with an expert provides environmental content knowledge, the mentor guides the students through tasks to complete the project. Sending a survey home to see if guardians have related skill sets and are willing to help out is a way to build connections with your students’ families.
Achieve goals: What are low-hanging fruits for the students to accomplish first to feel successful? Some projects take time, and their efforts may be the first steps toward a larger project. After a step from your plan is achieved, identify the next step, and create an associated goal within a realistic time frame. Celebrate your success as each goal is completed.
A Closer Look at Apprenticeships
The apprenticeship model helps intentionally build long-lasting mentorships with community partners and experts in the field in order to improve our program and student learning outcomes. In the beginning, our students secured community volunteers to help haul recyclables and worked alongside them to learn unloading procedures. My students began meeting with our neighboring county’s Solid Waste Authority’s director of education, taking tours of their large-scale recycling operations in order to learn the recycling ropes to create a sustainable operation in our county.
One of our students’ grandmothers became a board member of our county’s Solid Waste Authority, and she continues to work with our students biweekly to solve logistical problems and determine new outreach possibilities with our students. Other businesses, like Alpha Metallurgical Resources, reached out to us, and several students work directly with their environmental compliance manager to plan biannual Adopt-A-Highway litter clean-up events. Working alongside community members and experts in the field to solve a critical community issue nurtured my students’ leadership capabilities and confidence.
Creating a Lasting Legacy
Middle and high school students can develop ingenious solutions to problems such as air and water pollution, threatened species, and the lack of green space. At the same time, taking students outdoors jump-starts learning by awakening the senses and increasing connectedness and happiness. Through goal setting, hard work, and problem-solving, our recycling program grew and now serves as the only plastic recycling location in our entire county.
If a recycling program isn’t a good fit for your school, there are myriad other projects that students can pursue, such as doing a survey of microplastics or coming up with technological solutions to environmental challenges. Both the EPA’s Microplastic Beach Protocol for freshwater or marine waters and The Big Microplastic Survey provide citizen science opportunities for students to collect and report data, and Samsung’s Solve for Tomorrow gives students a chance to win classroom technology.
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