What is the use of Map.ofEntries() instead of Map.of()

Question

From the documentation of Map.java -

The Map.of() and Map.ofEntries() static factory methods provide a convenient way to cre

Answer 1

Java 9 introduced creating small unmodifiable Collection instances using a concise one line code, for maps the signature of factory method is:

static  Map of(K k1, V v1, K k2, V v2, K k3, V v3)

This method is overloaded to have 0 to 10 key-value pairs, e.g.

Map map = Map.of("1", "first");
Map map = Map.of("1", "first", "2", "second");
Map map = Map.of("1", "first", "2", "second", "3", "third");

Similarly you can have up to ten entries.

For a case where we have more than 10 key-value pairs, there is a different method:

static  Map ofEntries(Map.Entry... entries)

Here is the usage.

Map map = Map.ofEntries(
  new AbstractMap.SimpleEntry<>("1", "first"),
  new AbstractMap.SimpleEntry<>("2", "second"),
  new AbstractMap.SimpleEntry<>("3", "third"));