The underscore character ( _ ) can no longer be used as a legal identifier name. Earlier attempts to remove the underscore in an identifier name were incomplete. The use of such would generate a combination of errors and warnings. With Java 9, the warnings are now errors. Consider the following sample code:
public class Java9Tests { public static void main(String[] args) { int _ = 319; if ( _ > 300 ) { System.out.println("Your value us greater than 300."); } else { System.out.println("Your value is not greater than 300."); } } }
The preceding code, in Java 8, will result in compiler warnings for int _ = 319; and if ( _ > 300 ) statements. The warning is as of release 9, '_' is a keyword, and may ...
