CODEWITHSUNDEEP
scala
jason
jason

Reputation: 65

Scala compilation warning and failure. Warning: This catches all Throwables

This is a simple scala code for checking prime number. When I compile at command prompt, I get the following warning. I thought I would care less for warning. But it didn't create the .class files. Can someone share what this warning means?

warning: This catches all Throwables. If this is really intended, use case _ : Throwable to clear this warning.

object PrimeNumber extends App {

        println("11 is prime number : " + checkPrimeNumber(11))
        println("111 is prime number : " + checkPrimeNumber(111))


    //Method for checking prime numbers between 1 and 100
    def checkPrimeNumber(num: Int) = {
     try {
            if (num < 1 || num > 100)
            throw new IllegalArgumentException("Number should be between 1 and 100")
        else
            isPrimeNumber(num)
        } catch {
            case e: IllegalArgumentException => e.printStackTrace()
            case _ => println("Exception has occurred!")
        }
}

//Non Functional Method for finding prime number
def isPrimeNumber(number: Int): Boolean = {
        var i = 2
        while (i <= number / 2) {
            if (number % i == 0) {
            return false
        }
            i += 1
        }
            true
 }

}

Upvotes: 1

Views: 947

Answers (1)

radumanolescu
radumanolescu

Reputation: 4161

It is dangerous to catch Throwable in Java, and even more in Scala. Instead, use this:

catch { case scala.util.control.NonFatal(e) => // do something }

See http://www.tzavellas.com/techblog/2010/09/20/catching-throwable-in-scala/

Upvotes: 5

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