Java Methods for Interviews

ImpJavaFunctions.md

Methods that can help you code quicker and better.

String/Array

toCharArray() //get char array of a String

charAt(int x) //get a char at the specific index

length() //string length

length //array size 

substring(int beginIndex) 

substring(int beginIndex, int endIndex)

Integer.valueOf() //string to integer

String.valueOf() //integer to string

Arrays.sort()  //sort an array

Arrays.toString(char[] a) //convert to string

Arrays.copyOf(T[] original, int newLength)

System.arraycopy(Object src, int srcPos, Object dest, int destPos, int length)

isEmpty() //checks whether a string is empty or not.

compareTo(String s) //compares two strings lexicographically
//The method returns 0 if the string is equal to the other string. A value less than 0 is returned if the string is less than the other //string (less characters) and a value greater than 0 if the string is greater than the other string (more characters).

compareToIgnoreCase(String s) //compares two strings lexicographically, ignoring lower case and upper case differences.

ArrayList

 Collections.min(List<T> list)
  
 Collections.max(List<T> list)
  
 indexOf(Object value)
  
 b.set(int index, Object newValue);