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You're reading from  Apache Spark 2.x for Java Developers

Product typeBook
Published inJul 2017
Reading LevelIntermediate
PublisherPackt
ISBN-139781787126497
Edition1st Edition
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Authors (2):
Sourav Gulati
Sourav Gulati
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Sourav Gulati

Sourav Gulati is associated with software industry for more than 7 years. He started his career with Unix/Linux and Java and then moved towards big data and NoSQL World. He has worked on various big data projects. He has recently started a technical blog called Technical Learning as well. Apart from IT world, he loves to read about mythology.
Read more about Sourav Gulati

Sumit Kumar
Sumit Kumar
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Sumit Kumar

Sumit Kumar is a developer with industry insights in telecom and banking. At different junctures, he has worked as a Java and SQL developer, but it is shell scripting that he finds both challenging and satisfying at the same time. Currently, he delivers big data projects focused on batch/near-real-time analytics and the distributed indexed querying system. Besides IT, he takes a keen interest in human and ecological issues.
Read more about Sumit Kumar

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Lexical scoping


Lexical scoping is also referred to as Static scoping. As per lexical scoping, a variable will be accessible in the scope in which it is defined. Here, the scope of the variable is determined at compile time.

Let us consider the following example:

public class LexicalScoping { 
   int a = 1; 
   // a has class level scope. So It will be available to be accessed 
   // throughout the class 
 
   public void sumAndPrint() { 
      int b = 1; 
      int c = a + b; 
      // b and c are local variables of method. These will be accessible 
      // inside the method only 
   } 
   // b and c are no longer accessible 
} 

Variable a will be available throughout the class (let's not consider the difference of static and non-static as of now). However, variables b and c will be available inside the sumAndPrint method only.

Similarly, a variable given inside lambda expressions are accessible only to that Lambda. For example:

list.stream().map(n -> n*2 ); 

Here n is lexically scoped to...

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Apache Spark 2.x for Java Developers
Published in: Jul 2017Publisher: PacktISBN-13: 9781787126497

Authors (2)

author image
Sourav Gulati

Sourav Gulati is associated with software industry for more than 7 years. He started his career with Unix/Linux and Java and then moved towards big data and NoSQL World. He has worked on various big data projects. He has recently started a technical blog called Technical Learning as well. Apart from IT world, he loves to read about mythology.
Read more about Sourav Gulati

author image
Sumit Kumar

Sumit Kumar is a developer with industry insights in telecom and banking. At different junctures, he has worked as a Java and SQL developer, but it is shell scripting that he finds both challenging and satisfying at the same time. Currently, he delivers big data projects focused on batch/near-real-time analytics and the distributed indexed querying system. Besides IT, he takes a keen interest in human and ecological issues.
Read more about Sumit Kumar