Please I need help! in Java

1. Method name: averageArrayValues Parameter(s): An int array of at least length 1. Return value: Returns a double value that is the sum of the array elements divided by the array length. The requirement of at least one value is to prevent a divide by zero possibility. Post-Condition: The array parameter is not changed. Example: Calling averageArrayValues([1,2]) should return 1.5.
2. MethodName: frequencyCount Parameter(s): An int array. The elements of the array can only be numbers from 0 to 9. Return value: A new int array of 10 integers. The value in the new array at index n is the number of times value n appears in the parameter array. Post-Condition: The array parameter is not changed. Example: Calling frequencyCount([0,0,1,1,1,7]) would return [2,3,0,0,0,0,0,1,0,0] since there are 2 zeroes and 3 ones and 1 seven, and no other digits in the parameter array.
3. Method name: reverseSound Parameter(s): A double array. Return value: Returns a double array that has its elements in reversed order from the parameter array. Post-Condition: The array parameter is not changed. Example: Calling reverseSound([0.1, 0.2, 0.3, 0.5]) should return a new array [0.5, 0.3, 0.2, 0.1]. You may not use Collections.reverse() for this.