How Does Java's Array Assignment Syntax Differ Inside and Outside of Declarations?

Array Assignment Syntax Outside of Declarations

Java's array initialization syntax differs depending on whether it's used in a declaration or an assignment.

Initializing with Array Literals

When declaring an array, array literals can be used to initialize its elements:

AClass[] array = {object1, object2};

Initializing with the new Operator

Outside a declaration, arrays can be initialized using the new operator, followed by the element count and subsequent assignments:

AClass[] array = new AClass[2];
array[0] = object1;
array[1] = object2;

Syntax Restrictions: Assigning Array Literals to Non-Declared Arrays

However, attempting to assign an array literal to a non-declared array variable is prohibited:

AClass[] array;
...
array = {object1, object2}; // Blocked by Java

This restriction is imposed by Java for reasons that may not be immediately apparent.

Workaround: Using new Operator with Array Literals

As a workaround, the following syntax can be used:

AClass[] array;
...
array = new AClass[]{object1, object2};

This approach combines the array creation and initialization into a single statement while adhering to Java's syntax rules.

Example

For example, consider the following code snippet:

public void selectedPointsToMove(cpVect coord) {

    if (tab == null) {
        if (arePointsClose(coord, point1, 10)) {
            cpVect[] tempTab = {point1};
            tab = tempTab;
        } else if (arePointsClose(point2, coord, 10)) {
            cpVect[] tempTab = {point2};
            tab = tempTab;
        } else {
            cpVect[] tempTab = {point1,point2};
            tab = tempTab;
        }
    }
}

Without the workaround, the code would require additional statements to initialize tempTab before assigning it to tab.

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