- 1 What is the use of enum in Java?
- 2 What is enum class in Java with example?
- 3 What is enum data type in Java?
- 4 When should I use enum in Java?
- 5 What is difference between enum and class in Java?
- 6 Is enum a data type?
- 7 Can enum class have methods?
- 8 Can we extend enum in Java?
- 9 Can we have enum inside enum?
- 10 Is enum string Java?
- 11 Can enum be private in Java?
- 12 Why is enum constructor private?
- 13 Is enum or constant better?
- 14 Why is enum better?
- 15 How do you create an enum value in Java?
What is the use of enum in Java?
Enums are used when we know all possible values at compile time, such as choices on a menu, rounding modes, command line flags, etc. It is not necessary that the set of constants in an enum type stay fixed for all time. In Java (from 1.5), enums are represented using enum data type.
What is enum class in Java with example?
An enum type is a special data type that enables for a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it. Common examples include compass directions (values of NORTH, SOUTH, EAST, and WEST) and the days of the week.
What is enum data type in Java?
The Enum in Java is a data type which contains a fixed set of constants. The Java enum constants are static and final implicitly. It is available since JDK 1.5. Enums are used to create our own data type like classes. The enum data type (also known as Enumerated Data Type ) is used to define an enum in Java.
When should I use enum in Java?
Enums are lists of constants. When you need a predefined list of values which do represent some kind of numeric or textual data, you should use an enum. You should always use enums when a variable (especially a method parameter) can only take one out of a small set of possible values.
What is difference between enum and class in Java?
An enum can, just like a class, have attributes and methods. The only difference is that enum constants are public, static and final (unchangeable – cannot be overridden). An enum cannot be used to create objects, and it cannot extend other classes (but it can implement interfaces).
Is enum a data type?
Enumeration (or enum ) is a user defined data type in C. It is mainly used to assign names to integral constants, the names make a program easy to read and maintain. The keyword ‘ enum ‘ is used to declare new enumeration types in C and C++. Following is an example of enum declaration.
Can enum class have methods?
An enum class can include methods and fields just like regular classes. When we create an enum class, the compiler will create instances (objects) of each enum constants.
Can we extend enum in Java?
No, we cannot extend an enum in Java. Java enums can extend java. lang. Enum class implicitly, so enum types cannot extend another class.
Can we have enum inside enum?
Enum class. We can also provide various values as enum -member variables with the enum constants. We can create abstract methods within an enum. In that case, all of the Enum constants will become abstract and will be required to implement declared abstract methods.
Is enum string Java?
The Java enum type provides a language-supported way to create and use constant values. By defining a finite set of values, the enum is more type safe than constant literal variables like String or int.
Can enum be private in Java?
The enum constructor must be private. You cannot use public or protected constructors for a Java enum. If you do not specify an access modifier the enum constructor it will be implicitly private.
Why is enum constructor private?
We need the enum constructor to be private because enums define a finite set of values (SMALL, MEDIUM, LARGE). If the constructor was public, people could potentially create more value. (for example, invalid/undeclared values such as ANYSIZE, YOURSIZE, etc.). Enum in Java contains fixed constant values.
Is enum or constant better?
Enums limit you to the required set of inputs whereas even if you use constant strings you still can use other String not part of your logic. This helps you to not make a mistake, to enter something out of the domain, while entering data and also improves the program readability.
Why is enum better?
An enum is a data type that contains fixed set of constants. An enum is just like a class, with a fixed set of instances known at compile time. Advantages of enum: enum improves type safety at compile-time checking to avoid errors at run-time.
How do you create an enum value in Java?
You cannot create an object of an enum explicitly so, you need to add a parameterized constructor to initialize the value (s). The initialization should be done only once. Therefore, the constructor must be declared private or default. To returns the values of the constants using an instance method(getter).