Answers for "Your invitation has expired or is no longer valid."

MatDatepicker: No provider found for DateAdapter. You must import one of the following modules at your application root: MatNativeDateModule, MatMomentDateModule, or provide a custom implementation

import {MatNativeDateModule} from '@angular/material';

how to check if the file has remaining without reading from it java

Scanner scanner = new Scanner(new File("filename"));
while (scanner.hasNextLine()) {
   String line = scanner.nextLine();
   // process the line
}