Can I declare a Java method with a fixed-sized array argument?

As albjerto's answer and the comments stated, Java offers no compile-time syntax to differentiate between parameters that are arrays of different sizes (although, at that answer states, you could check it in runtime).

The only (horrible) option for compile-time safety for this requirement I can think of is to unwrap the array and pass its elements as separate arguments. E.g.:

// so-called int[2] variant:
public void myMethod(int arg1, int arg2) {
    // Do something with the arguments
    // If you actually need an array, you could do:
    int[] arr = {arg1, arg2};
}

// so-called int[3] variant:
public void myMethod(int arg1, int arg2, int arg3) {
    // Your logic here...
}

// etc

With larger arrays this will become very cumbersome very quickly but for smaller arrays it may be a valid option.

No, you can't enforce array sizes for method parameters.

However, if you have an array with a fixed number of parameters, I wonder if instead you have a clearly defined object type (e.g. a 3-D cartesian coordinate), and as such you can declare such an object (e.g. Point3D), use that as a parameter, and that typing is obviously enforced.

Actually you can't, but still then you can implement something like this,

For boolean returning function,

static boolean fixedArrayFuncBool(int[] arr, int lengthOfArray) {
        if (arr.length == lengthOfArray) {
            return true;
        } else {
            return false;
        }
    }

For integer returning function,

static int fixedArrayFuncInt(int[] arr, int lengthOfArray) {
    if(arr.length == lengthOfArray) {
        return lengthOfArray;
    }
    else {
        return -1;
    }
}

These function just check whether the given array is of the length that you give and return the value according to it.