Fall-through occurs when a series of executable statements after a case label is not guaranteed to transfer control before the next case label. For example, this can happen if the branch is missing a break statement. In that case, control falls through to the statements after that switch label, even though the switch expression is not equal to the value of the fallen-through label. While occasionally intended, this construction is confusing and is often the result of a typo.

This inspection ignores any fall-through commented with a text matching the regex pattern (?i)falls?\s*thro?u.

There is a fix that adds a break to the branch that can fall through to the next branch.

Example:

    switch(x) {
      case (4):
          if (condition) {
              System.out.println("3");
              // no break here
          } else {
              break;
          }
      case (6):
          System.out.println("4");
    }

After the quick-fix is applied:

    switch(x) {
        case (4):
            if (condition) {
                System.out.println("3");
            } else {
                break;
            }
            break;
        case (6):
            System.out.println("4");
    }