Why enum

You assigned two elements, i. Valkyrie, whose value is to the speed1 enum variable, and Roadster, whose value is to the enum variable speed2. You assigned these integer values with a power of 2 to avoid overlapping. This is because you want to use two flags at once, i. CameraQuality and LargeStorage. Therefore, the power of 2 with the integer values will not let overlapping occur while using the bitwise operator. You have set the flags CameraQuality and LargeStorage because you want a mobile with both features.

You also learned Enums with flags and how you can change the default values of the elements. Using enums increase the level of abstraction and lets the programmer think about what the values mean rather than worry about how they are stored and accessed.

This reduces the occurrence of bugs. Here is an example. We have a set of traffic lights with three bulbs- red , yellow and green. In the UK, the sequence of traffic lights changes in these four phases. The lights are controlled by writing to the bottom three bits of a control byte. These are laid out as a bit pattern below in binary where RYG represent the three bits. If R is 1, the red light is on etc. By using enums we prevent problems with other bits being assigned to the bulb control byte.

It might be that some of the other bits control self-testing or a "Green Lane" switch. In that case, a bug that allows these bits to be set in normal use could wreak havoc. To be sure, we'd mask the bits in the SetTrafficlights function so no matter what value is passed in, only the bottom three bits are changed. In Java from 1. In Java, we can also add variables, methods and constructors to it. The main objective of enum is to define our own data types Enumerated Data Types.

Attention reader! Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. Declaration of enum in java : Enum declaration can be done outside a Class or inside a Class but not inside a Method. RED; System. According to Java naming conventions , it is recommended that we name constant with all capital letters Important points of enum : Every enum is internally implemented by using Class.

Java import java. Every enum constant is always implicitly public static final. Since it is static , we can access it by using the enum Name. We can declare the main method inside the enum. Hence we can invoke enum directly from the Command Prompt. Enum class.

As a class can only extend one parent in Java, so an enum cannot extend anything else. Example for Level myVar : Level. Difference between Enums and Classes An enum can, just like a class , have attributes and methods. Report Error. Your message has been sent to W3Schools. W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning.