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Hi there.
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So, let’s begin the chapter by getting a high-level understanding of what Java is.
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We will also see how Java is being used in the industry
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So, what is Java? Java can be broadly defined as, a general-purpose, object-oriented, platform independent, 
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concurrent programming language that runs very fast
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General-purpose implies that, it’s not constrained to one particular domain and can be used to develop wide 
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variety of applications.
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Java is an object-oriented programming language and object-orientedness helps model real-world scenarios 
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in a more natural way. The concept of object and object oriented programming will be introduced later
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Java’s mantra is Write Once, Run Anywhere, i.e., you write a program once and you must be able to run it 
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on any platform regardless of the operating system & architecture.
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And this is referred to as platform independence. It is one of the key benefits of Java. Later in
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the chapter.
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we will see how this goal is achieved 
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in Java. Java supports concurrent programming, which is nothing but multi-threading; and this enables programs
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to perform multiple activities at around the same time. Java is also very fast. It is almost indistinguishable
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from C & C++. Later in the section
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we will look at certain aspects of the Java platform, which make Java programs run very fast
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These are some core attributes of Java. And these attributes make Java, a really solid, a very reliable
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and a complete programming language.
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It is currently one of the most widely used programming languages.
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Java was also built on few additional principles and 
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let’s look at some of them. Java was invented in the mid nineties and most programmers during early nineties
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were using C and C++.
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So, Java’s designer’s wanted to keep the syntax familiar;
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and so Java’s syntax is kept similar to C & C++. Simplicity was one of the most important goals for 
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Java’s designers.
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So, in comparison to C & C++, they wanted Java to be easy to use.
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For this reason, Java doesn’t have many features, which make C & C++ complex, confusing, and unsafe
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One example is related to memory management. In C & C++, programmers directly manipulate memory to free 
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up space.
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And if this is not done properly it can result in programs getting crashed.
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In contrast Java is simple and safer as it provides automatic memory management using a feature called
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garbage collection; and this relieves programmers from directly manipulating memory which in turn makes
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programming task easier.
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Garbage collection will be discussed in detail in the JVM internals chapter. Java is also secure.
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And this is very important as Java programs can be downloaded from across the network and the downloaded
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programs should not cause any harm to the user's computer.
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So, we looked at some of the key principles of Java.
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However, there are few other nice things that Java has to offer.
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One of them is that Java comes with a rich library, which includes extensive pre-defined functionality and this
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library is the Java API where API as you may know stands for Application Programming Interface.
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This helps developers to focus on writing new logic without having to re-invent the wheel
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i.e., they can simply make use of the pre-defined functionality, which is written by experts and is
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already being used by millions of programmers. Java is also free.
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And that's great for everyone including startups and even individual programmers.
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It would help them to develop and launch their own products without having to invest a lot in the
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software.
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As we will see later, Java was initially developed to run inside embedded systems and later within 
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Web browsers in the form of Java programs called applets.
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However it soon evolved as a popular language for developing large-scale Web applications, standalone desktop
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applications and mobile applications.
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Java provides separate dedicated platforms just for these different types of applications.
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And this slide highlights how widely Java is adopted. All these large companies like Google, Netflix, Amazon
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use Java. For instance,
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Gmail is mostly written in Java.
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Java was also used by NASA for their Mars Rover project called Spirit.
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It seems one of the reasons they picked Java is due to its platform independence capability; and this also
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tells that Java is truly general-purpose programming language
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, i.e., it is not constrained to only commercial space.
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Also, when it comes to open source libraries, probably most number of open source libraries are implemented
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in Java. And the libraries that we see here are extremely popular.
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For instance, companies like eBay & Apple use Apache Solr for providing search capability within
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their Websites. Java is also extremely popular in domains such as search, data mining and machine learning, 
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which are very hot right now and they typically deal with very huge amounts of data. And here is a Job
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requirement for a machine learning engineer position from Amazon.com in Bangalore, India.
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And as we can see here the requirement is a solid understanding
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in Java and object-oriented design; and this course is all about acquiring these skills.
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So, that’s about what Java is? It was mainly designed to be simple, platform independent, and also very 
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stable and secure.
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Performance wise it is very fast.
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It supports concurrent programming and comes with a rich library
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Thank you.