Question

What is the scope of static classes used in el language?

I assume application scope?

I tested it in debug mode and that lazy loaded attribute is only initialized once in multiple windows, browsers.

private static Object[] objects = null;

public static Object[] getObjects()
{
    if(ElClass.objects == null)
        //init objects
    return ElClass.objects;
}

Answer 1

There is no means of a concrete instance. The EL functions class is not even constructed. EL functions are intented to be entirely stateless. Static variables are per definition JVM-wide (or application wide as you call it). In normal Java code you would also just do ELClass.getObjects() instead of new ELClass().getObjects().

As to your particular example, I recommend to do the initialization just in a static initializer block. That lazy loading is unnecessary.

private static final Object[] objects;

static {
    // Init objects.
}

public static Object[] getObjects() {
    return objects;
}

I also recommend to add a private constructor so that you prevent that the functions class can ever be constructed.

private ELClass() {
    // Prevent construction.
}