The case keyword is used inside switch block. Together they form a switch-case block which is used to evaluate condition and execute a corresponding case block based on the outcome of condition.
Example of case keyword
There are multiple cases inside a switch block. Based on the outcome of the condition specified in parentheses, a case block executes. Each case block except the default block is terminated using break keyword, this prevents the execution of next case block.
public class JavaExample {
  public static void main(String[] args) {
    int month = 6;
    switch (month) {
      case 1:
        System.out.println("January");
        break;
      case 2:
        System.out.println("February");
        break;
      case 3:
        System.out.println("March");
        break;
      case 4:
        System.out.println("April");
        break;
      case 5:
        System.out.println("May");
        break;
      case 6:
        System.out.println("June");
        break;
      case 7:
        System.out.println("July");
        break;
      case 8:
        System.out.println("August");
        break;
      case 9:
        System.out.println("September");
        break;
      case 10:
        System.out.println("October");
        break;
      case 11:
        System.out.println("November");
        break;
      case 12:
        System.out.println("December");
        break;
      default:
        System.out.println("Enter a valid number (1-12)");
    }
  }
}
Output:
June