The following method generates an OutOfMemoryError, how to overcome that?

[Varuna Seneviratna]

The following method generates an OutOfMemoryError.How is it possible to generate a random integer which can be used as the number of elements of an ArrayList Or Array that won't generate an OutOfMemoryError.

    /**
* Randomly generates the number of elements of the ArrayList
* Then randomly adds elements up to the number of elements which was   randomly generated
* At last Returns a randomly selected responce

*/

public String randomResponse()
{

    int numberOfResponses=randomNumberGenerator.nextInt();
    ArrayList randomList=new ArrayList<String>();

    if(numberOfResponses > 0) 
    {
        for(int i=0; i <numberOfResponses; i++)
        {
            int responseIndex=randomNumberGenerator.nextInt(3);
        
            if(responseIndex==0)
            {
                randomList.add("No");
            }
            else if(responseIndex==1)
            {
                randomList.add("Yes");    
            }
            else{
                randomList.add("May be");
            }
            
        }
    }
    int randomResponse=randomNumberGenerator.nextInt(randomList.size() - 1);
        return (String)randomList.get(randomResponse);

}

>

[Ernest Friedman-Hill]

The problem is here, of course:

int numberOfResponses=randomNumberGenerator.nextInt();

numberOfResponses can be negative (in which case the loop won't run at all!) or it can be an enormous number near Integer.MAX_VALUE (in which case randomList will grow large and you'll get an OutOfMemoryError.

In any case, all of this is unnecessary to the point of being silly. The answer is no more or less random than simply saying

return new String[] {"No", "Yes", "Maybe"}[randomNumberGenerator.nextInt(3)];

[Campbell Ritchie]

Have you read what the nextInt() method returns, and what the maximum size of your List would be?

[Campbell Ritchie]

I see Ernest has beaten me to it!

[Fred Hamilton]

for my own edification, is not the statement...

if(numberOfResponses > 0) {

redundant here? cause if numberOfResponses is 0 or negative, then the for condition causes the for block not to be executed even once?

[Ernest Friedman-Hill]

Fred Hamilton wrote:if numberOfResponses is 0 or negative, then the for condition causes the for block not to be executed even once?

ABsolutely right.

[Brian Legg]

Fred, you beat me to nitpicking this as well

[Fred Hamilton]

Brian Legg wrote:Fred, you beat me to nitpicking this as well

OK my friend, I'll try try not to pick all the easy nits then