Scala Constructor

In scala, constructor is not special method. Scala provides primary and any number of auxiliary constructors. We have explained each in details in the following example.

Scala Default Primary Constructor

In scala, if you don't specify primary constructor, compiler creates a constructor which is known as primary constructor. All the statements of class body treated as part of constructor. It is also known as default constructor.

Scala Default Primary Constructor Example

Output:

Hello from default constructor

Scala Primary Constructor

Scala provides a concept of primary constructor with the definition of class. You don't need to define explicitly constructor if your code has only one constructor. It helps to optimize code. You can create primary constructor with zero or more parameters.

Scala Primary Constructor Example

Output:

101 Rama

Scala Secondary (auxiliary) Constructor

You can create any number of auxiliary constructors in a class. You must call primary constructor from inside the auxiliary constructor. this keyword is used to call constructor from other constructor. When calling other constructor make it first line in your constructor.

Scala Secondary Constructor Example

Output:

101 Rama 20

Scala Example: Constructor Overloading

In scala, you can overload constructor. Let's see an example.

Output:

101
100
100 India