Utility Methods (java.util)

1. Sorting

• Arrays.sort() - returns sorted arrays (arr), by quicksort methods,uses java.util.Arrays lib
  Arrays.sort(arr);
  • To sort Sub Array in range of start and end
    Arrays.sort(arr, int start, int end);
  • To sort array in Decending (Reverse) order using Collections.reverseOrder(); as argument
    Arrays.sort(arr, Collections.reverseOrder());
• Collection.sort() - sorting of lists like ArrayList, LinkedList, etc. , uses java.util.Collections lib
  Collections.sort(list);
  • To sortlist in Decending (Reverse) order using Collections.reverseOrder(); as argument
    Collections.sort(arr, Collections.reverseOrder());

2. Searching

• Arrays.binarySearch() - returns the position, searching a key value in Array using Binary Search
  int n = Arrays.binarySearch(datatype arr, datatype key);
• Collections.binarySearch() - returns the position, searching a key value in list using Binary Search
  int n = Collections.binarySearch(List list, T key);

3. Copying

• Arrays.copyOf() - copy the contents of array to a new array with legth newLength
  int[] newArray = Arrays.copyOf(int[] arr, int newLength);

4. Rotate

• Collection.rotate() - Rotate the list by distance, the element present at (i) will rotate to (i-distance)% list.size();
  Collection.rotate(List list, int distance);

4. Frequency

• Collection.frequency() - returns frequency of Object (o) in the list
  int n = Collection.frequency(List list, Object o);

5. Get Max

• Collection.max() - returns maximum of all elements in the list
  datatype n = Collection.max(List list);