What is the purpose of the underscore keyword in Java 9?

In earlier versions of Java, the underscore ("_") has been used as the identifierOr create variable name. Starting with Java 9, the underscore character is a reserved keyword and cannot be used as an identifier or variable name. If we use a single underscore character as an identifier, the program will fail to compile and throw a compile-time error because now it is a keyword, and cannot be used as a variable name in Java 9 or later.

Example

public class UnderscoreKeywordTest {
   public static void main(String args[]) {
      int _ = 50
      System.out.println(_);
   }
}

Output

<strong>UnderscoreKeywordTest.java:3: error: as of release 9, &#39;_&#39; is a keyword, and may not be used as an identifier
int _ = 50;
^
UnderscoreKeywordTest.java:4: error: as of release 9, &#39;_&#39; is a keyword, and may not be used as an identifier
System.out.println(_);</strong>

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