In Java you can find maximum or minimum value in a numeric array by looping through the array. Here is the code to do that.

public static int getMaxValue(int[] numbers){
  int maxValue = numbers[0];
  for(int i=1;i < numbers.length;i++){
    if(numbers[i] > maxValue){
	  maxValue = numbers[i];
	}
  }
  return maxValue;
}

public static int getMinValue(int[] numbers){
  int minValue = numbers[0];
  for(int i=1;i<numbers.length;i++){
    if(numbers[i] < minValue){
	  minValue = numbers[i];
	}
  }
  return minValue;
}

These are very straight forward methods to get maximum or minimum value of an array but there is a more cleaner way to do this. More