solve by Java 11.4 (Maximum element in ArrayList) Write the following method that returns the maximum value in an ArrayList of integers. The method returns nul1 if the list is nu11 or the list size is 0. public static Integer max(ArrayList 1ist) Write a test program that prompts the user to enter a sequence of numbers ending with 0 and invokes this method to return the largest number in the input.

1. Write a recursive method expFive(n) to compute y=5^n. For instance, if n is 0, y is 1. If n is 3, then y is 125. If n is 4, then y is 625. The recursive method cannot have loops. Then write a testing program to call the recursive method. If you run your program, the results should look like this: > run RecExpTest Enter a number: 3 125 >run RecExpTest Enter a number: 3125 2. For two integers m and n, their GCD(Greatest Common Divisor) can be computed by a recursive function. Write a recursive method gcd(m,n) to find their Greatest Common Divisor. Once m is 0, the function returns n. Once n is 0, the function returns m. If neither is 0, the function can recursively calculate the Greatest Common Divisor with two smaller parameters: One is n, the second one is m mod n. Although there are other approaches to calculate Greatest Common Divisor, please follow the instructions in this question, otherwise you will not get the credit. Meaning your code needs to follow the given algorithm. Then…

The following recursive method get Number Equal searches the array x of 'n integers for occurrences of the integer val. It returns the number of integers in x that are equal to val. For example, if x contains the 9 integers 1, 2, 4, 4, 5, 6, 7, 8, and 9, then getNumberEqual(x, 9, 4) returns the value 2 because 4 occurs twice in x. public static int getNumberEqual(int x[], int n, int val) { if (n< 0) ( return 0; } else { if (x[n-1) == val) { return getNumberEqual(x, n-1, val) +1; } else { return getNumber Equal(x, n-1, val); } // end if ) // end if } // end get Number Equal Demonstrate that this method is recursive by listing the criteria of a recursive solution and stating how the method meets each criterion.

/*In this program you need to implement four methods with the following signatures:printArr(int[] a)add(int[] a, int[] b)subtract(int[] a, int[] b)negate(int[] a) 1. Method printArr(a) should print out all elements of a given int array in one line.   2. Method add(a, b) should take two int arrays (assume they have the same length) and return a new array each element of which will be the sum of the corresponding elements in a and b   3. Method subtract(a, b) is similar to add(), except it returns (a - b) array   4. Method negate(a)takes an int array and returns a new array in which every element is multiplied by -1.  */ public class ArrayOperations{     public static void main(String[] args){        //The main only has the testing code.        //You don't have to change it.         int [] a = { 1, 2, 3, 4, 5};        int [] b = {10, 1, 3, 5, 7};        System.out.print("a = ");        printArr(a);//Should print each element of a (in one line)        System.out.print("b = ");…