List of fixed size Arrays in Java?

Question

Is it possible to create a List of arrays(with fixed size) in Java?

I have tried these methods and they both give me a syntax error:

List<int[]> failedParameters = new ArrayList<int[3]>();
List<int[]> failedParameters = new ArrayList<new int[3]>();

What am I doing wrong?

Answer 1

No, you can't specify the array length as a Java type. However, you can wrap arrays in your own type. I'll let you decide if that is really practical (in case you have dozens of array lengths that you want to support):

class Int3 {
    // Use final to indicate that the array length will remain unchanged
    final int[] array = new int[3];
}

List<Int3> failedParameters = new ArrayList<Int3>();

Of course, if you go this far, why not just create an int-tuple of degree 3?

class Int3 {
    int v1;
    int v2;
    int v3;
}

List<Int3> failedParameters = new ArrayList<Int3>();

Answer 2

You can use this method. It will not allow you to change the collection size (no add()/remove() operations).

List<> unmodiffableList = Collections.unmodifiableList(oListeRet);