[JAVA] Using Pair with OpenJDK

Abstract: You can instantiate java.util.AbstractMap.SimpleEntry instead of javafx.util.Pair, even in OpenJDK or Java7 (or lesser).

--Sometimes you want to use key / value pairs, or pairs, in competitive programming. --The scripting language allows you to put multiple types of values in an array. --There is support for pairs in compilation languages, such as std :: pair in C ++, System.Collections.Generic.KeyValuePair and System.Tuple in C #, and Tuple in Crystal. --On the other hand, Java does not have pair support. --A class called javafx.util.Pair was introduced in Java8, but not in OpenJDK. --Aside: In yukicoder, my answer was once AC, but it became CE because Sun Java was changed to OpenJDK.

--There is java.util.Map.Entry with the same interface, but this cannot be instantiated. --When I investigated this, I found that I should use the class java.util.AbstractMap.SimpleEntry.

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