Java - trouble in calling a method

Question

I have a sorting method created in a class separate from the class I am currently working in. The sorting method is a public static void method named:

public static void sortSelection(Comparable[] array, int n)

In the class where I currently work, entitled "Library", I wish to call upon this method as part of a different sorting method which I simply call "sort". So, I have written as follows:

public void sort() {
sortSelection(CDCollection, numberOfCDs)
}

where CDCollection is an array, and numberOfCDs is an integer. However, I get the error message:

"The method sortSelection(CD[], int) is undefined for the type Library"

If anyone knows whay may cause this error, I would greatly appreciate it!

Answer 1

You call a static method on a class by providing the class name. Something like this:

public void sort() {
    OtherClassName.sortSelection(CDCollection, numberOfCDs)
}

Answer 2

you need to call the other class before using its method

public void sort()
{
     ClassName.sortSelection(array, int);
}