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How are enums internally represented in java?


Asked by Kase Holmes on Dec 03, 2021 Java



The EnumSet<T> is a specialized Set implementation to be used with enum types. They are represented internally as bit vectors. The elements in an enum set must have a single enum type and Null elements are not allowed in the set. The EnumSet<T> cannot be instantiated using a constructor; instead, there are many factory methods to do the same.
And,
1 Enums. An enum is a special "class" that represents a group of constants (unchangeable variables, like final variables). 2 Enum inside a Class 3 Enum in a Switch Statement 4 Loop Through an Enum. The enum type has a values () method, which returns an array of all enum constants. ...
Thereof, EnumSet is a high-performance Set implementation for enums. All of the members of an enum set must be of the same enum type. Internally, it is represented by a bit-vector, typically a single long. Enum sets support iteration over ranges of enum types.
Also,
So, we have enum constants in capital letters. Java Enums can be thought of as classes which have a fixed set of constants (a variable that does not change). The Java enum constants are static and final implicitly. It is available since JDK 1.5.
In fact,
The EnumSet class provides a static factory that makes it easy: Similarly, EnumMap is a high-performance Map implementation for use with enum keys, internally implemented as an array. Enum maps combine the richness and safety of the Map interface with speed approaching that of an array.