Scala

Introduction

Why Scala?

1. Blend of Functional and object oriented language(provides Best of both)
2. Use of immutable Data structures (value of variable intact so less bug prone)
3. Rich Collection library
   1. Library is divided in mutable and immutable Data Structure.
   2. Collection which can be lazy or can be eager in its evaluation.
   3. Provides collection that can run in parallel that speed up processing.
4. Better concurrency support
   1. Leverage multi-core machine capability without needing us to do more
   2. In Java we have to do a lot of low level task of handling the threads e.g
      1. Acquiring and releasing the lock (synchronised/static synchronised),this is simplified in Scala.
   3. concurrency is first class citizen in Scala

Scala frameworks are Play, Lift whereas Java frameworks are Spring, Grails, and many more.

Parameter	Scala	Java
Compactness	More compact and concise	Comparatively larger chunks of code
Designed for	It is designed and developed to be both object and functional oriented language. It supports a wide variety of functional programming features such as concurrency and Immutability.	Originally developed as an object-oriented language and started supporting functional programming features in recent days. It is not as strong as a functional programming language.
Concurrency model	Uses actor model for supporting modern concurrency	It uses the conventional thread-based model for concurrency.
Supported frameworks	Supports frameworks – Play, Lift	Supports Spring, Grails, much more
Lazy evaluation support	Supports lazy evaluation	Does not support lazy evaluation
Static members	No static members	Contains static members
Operator overloading	Supports operator overloading	Does not support operator overloading
Compilation process	Compilation of source code is comparatively slow	Compilation of source code is faster than Scala
Interfaces	Traits – act like Java 8 interfaces	Java 8 interfaces try to bridge the gap between classes and interfaces
URL rewriting	Rewriting is needed	Rewriting is not required
Bug-free codes	No assurance about the bug-free codes	Complete assurance of lesser defects
Support for backward compatibility	Scala does not support backward compatibility	Java supports backward compatibility
Support for Multiple inheritances	Supports multiple inheritances using classes but not by abstract classes	Does not support multiple inheritances using classes, but by interfaces
Code style	Code is written in a compact form.	Code is written in long-form.
Static keyword	Scala does not contain the static keyword.	Java contains the static keyword.
Treats	Any method or function present in Scala is they are treated like they are variable.	Java treats functions as an object.
Type of variables	Scala variables are by default immutable type.	Java variables are by default mutable type.
Object orientation	Scala treats everything as an instance of the class and it is more object-oriented language as compare to Java.	Java does not support operator overloading.
Calling method	In Scala, all the operations on entities performed using method calls.	Operators are treated differently and is not done using the call method.
Readability	Scala is less readable because of its nested code.	Java is more readable.
Compiling process	Compiling the process of source code into byte code is very slow.	Compiling the process of source code into byte code is fast.

Installation

1. sudo apt-get install scala
2. Verification
   1. scala -version
3. IDE
   1. easy integration with intellij – install and
      1. add plugin scala

Scala Versions

1. Latest V3
2. before this was version 2