What is the exact meaning of instantiate in JAVA

Question

I\'am a newbie in JAVA and this came across this word called. \"A class i.e. created inside a method is called local inner class in java. If you want to invoke the methods o

Answer 1

Instantiate in Java means to call a constructor of a Class which creates an an instance or object, of the type of that Class. Instantiation allocates the initial memory for the object and returns a reference. An instance is required by non-static methods as they may operate on the non-static fields created by the constructor.

Static methods don't need an instance and should not be stateful, i.e. should not rely on changing data. They are essentially free functions that are associated with the type and not a particular instance. When you want to work with changing data, encapsulating that data as member fields that are operated on by instance methods is the way to go.

For example, a Car class might have static numbeOfWheels() that always returns 4, but an instance numberOfFlatTires() that might return 0-4 depending on the state of that particular Car.

Inner classes are no different and the only difference between a static and non-static inner class is that the non-static can use the parent instance's members. This can be used to reduce complexity. You might have a looping operation that has a common parameter for the list and an individual parameter for the items. You could use a non-static inner class to encapsulate the operations on the item while referring to the common parameter in the parent class.

Enums are special in that each value is a single instance of a single type that all extend from a common abstract base class defined in the Enum class body. The Enum value is instantiated the first time it's used, but there will only ever be one instance per value.