Java Enum Faq - What Every Coffee Developer Should Know Most Enumeration Type

Java Enum was i of the best features added on JDK 1.5 Tiger liberate along amongst Generics, Autoboxing, in addition to varargs. Enum inwards Java represents fixed publish of well-known things e.g. publish of days inwards Week, the publish of months inwards the calendar yr etc. Unlike C in addition to C++ Enum inwards Java are much powerful in addition to they are non an integer constant, Instead, Enum is a Type similar shape or interface which provides compile fourth dimension type safety. In this Java Enum tutorial, nosotros volition run across a span of of import points close Java Enum which help to empathise Enum amend in addition to acquire most out of it. I convey written inwards the manner of FAQ i.e. ofttimes asked questions, this volition help yous to larn to a greater extent than close Java Enum's capability in addition to features e.g. whether Enum tin extend shape or implement methods or not? When yous tin override methods within enum? whether yous tin compare Enum using equals() or == inwards Java? etc

Java Enum FAQ - Frequently asked Questions

As I told yous enum or enumeration type inwards Java is i of the of import concepts inwards Java. It's non only plenty to larn close shape in addition to interface, yous besides convey to larn close Enumeration type. In this article, I volition respond or hence of the ofttimes asked questions based upon Java Enum, these volition help yous to larn the concept amend in addition to motivate yous to explore past times yourself.



What is Enum inwards Java?

Enum is Java produce much similar a shape in addition to interface which is used to stand upward for fixed publish of well-known things e.g. days of the week, months of a yr etc.

What is the role of Enum inwards Java?

As I told inwards the previous example, yous tin role Enum to stand upward for fixed publish of things e.g. yous tin role it stand upward for the states of your application e.g. threads states similar Runnable, Running, Stopped etc. You tin besides role it to implement Strategy pattern. You tin role Enum to write thread-safe Singleton, in addition to fifty-fifty to produce your ain acre automobile inwards Java. 

What is the divergence betwixt C, C++ enum in addition to Java Enum?

Unlike C in addition to C++, Enum inwards Java are non integer constant, they are classes, similar to whatever interface or class. Because of this argue Enum inwards Java provides type safety in addition to compile time checking which was non possible amongst enum int pattern. Java Enum is a full-fledged type in addition to yous tin role it equally shape or interface.

Can Enum extend a Class inwards Java?
No, Enum cannot extend a Class inwards Java. Every Enum inwards Java extends from java.lang.Enum implicitly in addition to because of this Enum tin non extend whatever other shape inwards Java.

Can Enum convey Constructor inwards Java?

Enum inwards Java doesn't convey a populace constructor. This way yous tin non produce an additional instance of Enum instances other than what is created from Enum shape itself in addition to available at compile time. Enum tin convey a private constructor, though.

Can yous declare methods within Enum inwards Java?
Yes, yous tin declare methods inwards Java Enum in addition to yous tin even override in addition to overload them within private Enum instances. For example, yous convey declared a Color enum which has a method getHexCode(). Now, yous declare 4 colors or enum constants inwards Color enum e.g. RED, BLUE, GREEN, WHITE, BLACKand in addition to hence yous tin override getHexCode() method to render hex code for these color e.g. RED volition render 0xFF0000 in addition to BLACK volition render 0x000000.

You tin farther read Core Java, Volume 1 - Fundamentals past times Cay S. Horstmann to larn to a greater extent than close advanced features of Enum inwards Java.

Can yous alter the value of Enum instance inwards Java?

Enum values or Enum instances are public, static in addition to final inwards Java. They are a compile-time constant, which way yous tin non changes values of Enum instances in addition to farther assignment volition lawsuit inwards compile fourth dimension error.

Can Enum implement an interface in addition to override method inwards Java?

Yes, Enum inwards Java tin implement interface in addition to override methods. In fact, Java Enum implicitly implements Comparable interface in addition to override compareTo() method. You tin banking company correspond the code of java.lang.Enum shape to confirm this. 

How to compare 2 Enumeration inwards Java?
Enum instance inwards Java tin last compared using == equality operator or equals() method inwards Java. Enum provides the high-quality implement for equals() in addition to hashCode in addition to tin last used inwards Set in addition to Map. But for functioning reason, it's best to role EnumMap in addition to EnumSet spell storing enum inwards Collection.

How to compare same instances of the same Enum inwards Java?

When yous compare unlike instances of the same Enum type, they are compared inwards the guild on which they are declared inwards Enum. You tin acquire this guild past times calling the ordinal() method of Enum.

How to convert Enum to String inwards Java?

Enum provides implicit methods similar values(), ordinal() in addition to name() which tin last used to acquire all Enum instances equally an array, guild of enum equally declared inwards shape in addition to String cite of Enum instances inwards Java.

How to convert Enum to Array inwards Java?
You tin role Enum's values() to convert an Enum to array inwards Java. This method returns an array containing all Enum constants. See these examples to larn to a greater extent than close how to role values() method of java.lang.Enum inwards Java.


How to iterate over Enum inwards Java?

You tin role Enum's values() method tin last used to iterate over enum. It returns an array which tin last traversed using whatever loop constructs inwards Java, including Java 1.5 enhanced for loop.

That's all close or hence frequently asked questions close Enumeration type inwards Java. Enum is much powerful in addition to they convey used inwards unlike ways inwards Java programming language. yous tin fifty-fifty role Enum to produce thread-safe Singleton inwards Java. You tin besides supplant your quondam code which is written using enum int blueprint or enum String blueprint inwards Java.

If yous convey whatever questions related to Enum inwards Java in addition to hence delight driblet a comment in addition to I'll elbow grease to respond your questions. If yous desire to larn to a greater extent than yous tin farther read Head First Java, it explains Enum concepts quite well. 

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