Java Enum and Abstract Methods – 11th Hour

Java Enum and Abstract Methods – 11th Hour

I have found a useful tip while I was digging around the internet for a java business code. I am telling about using abstract methods inside an enum is very useful for implementing your business logic.

Before clear it up with examples about enum, let me tell few words about it.
An enum is a different type of class. The Java Language Specification says "There are two kinds of class declarations: normal class declarations and enum declarations. The body of an enum type may contain enum constants. An enum constant defines an instance of the enum type".

An enum type is a subclass of java.Lang.Enum. An enum cannot extend anything else, but still it can implement other interfaces. Public or protected modifiers can only be used with a top-level enum declaration, but all access modifiers can be used with nested enum declarations. Also an enum type provides final methods like name, compareTo, hashCode etc. We can also use as well as override toString() method in an enum.

No more no less. You can read the documentation here. Also you could get the Java Language Specification about enum from here.

Now come to an example. This is my Country enum. You can find an abstract method getCurrency() inside enum. If an abstract method is declared inside enum, it must be overridden in all the enum constant bodies.

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