static classes

[shaf maff]

Hi Guys

I have a static utilities class which holds common methods. I have several static methods which convert strings to longs, and vice versa and returns the value to the requesting method. My question is will this cause a problems if multiple users are making the same request at the same time ? See a snippet of code below:

	
        // Convert any string to long
	public static long toLong(String value) throws NumberFormatException {
		try {
			return parseToLong(value);
		} catch (NumberFormatException e) {
			throw new NumberFormatException("Invalid ID");
		}
	}

[Saifuddin Merchant]

No - Each user request will run in its own thread and since nothing is being share (no Synchronization) there should be no problem.

[Rob Spoor]

Only if these methods would use a shared static variable, and the methods change that variable, you could run into problems. If you only use local variables, or the shared variables are immutable (or you simply don't change them), there is no problem whatsoever.

For instance:

final class UtlityClass
{
    private static final String[] VALUES = {"1", "3", "4"};

    private static final Integer VALUE = Integer.valueOf(481);

    private UtilityClass() {} // prevent initialization

    public static Integer doSomething(String value)
    {
        for (String s: VALUES) // mutable object is only read, not changed
        {
            if (s.equals(value))
            {
                return VALUE; // immutable object can never change so safe
            }
        }
        return null;
    }
}