How to make a big array in java

Question

I want to create a boolean array of a size which the user is going to put as input.For example - The user might put a big number like 1000000000000 ; so then I have to creat

Answer 1

You could create an abstraction, for example array of arrays (you can even modify this).

Object [][] can be boolean or whatever.

class LargeArray {

    private final long size;
    private final int sizeI;
    private final int sizeJ;
    private final Object [][] objects;


    public LargeArray() {
        sizeI = 3;//Any reasonable value;
        sizeJ = Integer.MAX_VALUE;
        objects = new Object [sizeI][sizeJ];
        size = sizeI * sizeJ;
    }

    public long size() {
        return size;
    }

    public Object get(long index) {
         int i = index / sizeJ;
         int j = index % sizeJ;
         return objects[i][j];
    }

    public void set(long index, Object object) {
         int i = index / sizeJ;
         int j = index % sizeJ;
         objects[i][j] = object;
    }
}

You could also change first dimension, say 3. In this case Object [3][Integer.MAX_VALUE], you can create (2^31 -1)*3 = 2,147,483,647 * 3 = 6442450941 elements and you will need (2^31 - 1)*3 * 4 =~ 23 GB RAM, which is actually possible!!!:)