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);