Maps: EnumMap is the right map for enum keys

EnumMap is backed by an array indexed by ordinal, so it is compact, fast, and always iterates in enum declaration order.

Code

enum Status { NEW, ACTIVE, CLOSED }

var counts = new EnumMap<Status, Integer>(Status.class);
counts.put(Status.CLOSED, 5);
counts.put(Status.NEW, 2);
counts.put(Status.ACTIVE, 7);

System.out.println("iterates in declaration order: " + counts);
System.out.println("ACTIVE = " + counts.get(Status.ACTIVE));

Output

iterates in declaration order: {NEW=2, ACTIVE=7, CLOSED=5}
ACTIVE = 7

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Published 2026-07-30