Write a Java program to segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s.

Sure, here is a simple Java program that segregates all 0s on the left side and all 1s on the right side of a given array of 0s and 1s.

public class Main {
    static void segregate0and1(int arr[], int n) {
        int count = 0; // counts the no of zeros in arr

        for (int i = 0; i < n; i++) {
            if (arr[i] == 0) {
                count++;
            }
        }

        // loop fills the arr with 0 until count
        for (int i = 0; i < count; i++) {
            arr[i] = 0;
        }

        // loop fills remaining arr elements with 1
        for (int i = count; i < n; i++) {
            arr[i] = 1;
        }
    }

    // function to print segregated array
    static void print(int arr[], int n) {
        System.out.print("Array after segregation is ");
        for (int i = 0; i < n; i++) {
            System.out.print(arr[i] + " ");
        }
    }

    public static void main(String[] args) {
        int arr[] = new int[]{0, 1, 0, 1, 1, 1};
        int n = arr.length;

        segregate0and1(arr, n);
        print(arr, n);
    }
}

This program works by first counting the number of 0s in the array. Then it fills the array with 0s up to the count, and fills the rest of the array with 1s. The result is an array with all 0s on the left and all 1s on the right.