The compareTo() method compares the Number object that invoked the method to the argument. It is possible to compare Byte, Long, Integer, etc.However, two different types cannot be compared, both the argument and the Number object invoking the method should be of the same type.ExampleLive Demopublic class Test {    public static void main(String args[]) {       Integer x = 5;       System.out.println(x.compareTo(3));       System.out.println(x.compareTo(5));       System.out.println(x.compareTo(8));    } }Output1 0 -1

To find weather a string is rotation of another, concat the first string to itself twice and find weatherExample Live Demopublic class Sample {    public static void main(String args[]){       String str1 = "gala";       String str2 = "alag";       String s3 = str1+str1;       if(s3.contains(str2)) {          System.out.println("str1 is rotation of str2");       } else {          System.out.println("str1 is not rotation of str2");       }    } }

You can capitalize words in a string using the toUpperCase() method of the String class. This method converts the contents of the current string to Upper case letters.Example Live Demopublic class StringToUpperCaseEmp {    public static void main(String[] args) {       String str = "string abc touppercase ";       String strUpper = str.toUpperCase();       System.out.println("Original String: " + str);       System.out.println("String changed to upper case: " + strUpper);    } }OutputOriginal String: string abc touppercase String changed to upper case: STRING ABC TOUPPERCASE

The replaceAll() method of the String class replaces each substring of this string that matches the given regular expression with the given replacement. You can remove white spaces from a string by replacing " " with "".ExampleLive Demoimport java.io.*; public class Test {    public static void main(String args[]) {       String Str = new String("Hi how are you Welcome to Tutorialspoint.com");       System.out.print("Return Value :" );       System.out.println(Str.replaceAll(" ", ""));    } }OutputReturn Value :HihowareyouWelcometoTutorialspoint.com

The charAt() method of the String class returns the char value at the specified index. An index ranges from 0 to length() - 1. The first char value of the sequence is at index 0, the next at index 1, and so on, as for array indexing.The indexOf(int ch, int fromIndex) method of the String class returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.If a character with value ch occurs in the character sequence represented by this String object at an index no smaller than fromIndex, then the index of ... Read More

The parseXxx() method is used to get the primitive data type of a certain String. In this case to convert a String to integer you could use the parseInt() method.Example Live Demopublic class Test {    public static void main(String args[]) {       int x =Integer.parseInt("9");       double c = Double.parseDouble("5");       int b = Integer.parseInt("444",16);       System.out.println(x);       System.out.println(c);       System.out.println(b);    } }Output9 5.0 1092

We can verify whether the given string is empty using the isEmpty() method of the String class. This method returns true only if length() is 0.Example Live Demoimport java.lang.*; public class StringDemo {    public static void main(String[] args) {       String str = "tutorialspoint";       // prints length of string       System.out.println("length of string = " + str.length());       // checks if the string is empty or not       System.out.println("is this string empty? = " + str.isEmpty());    } }Outputlength of string = 14 is this string empty? = false

The replace() method of the returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.Example Live Demoimport java.io.*; public class Test {    public static void main(String args[]) {       String Str = new String("Welcome to Tutorialspoint.com");       System.out.print("Return Value :" );       System.out.println(Str.replace('o', 'T'));       System.out.print("Return Value :" );       System.out.println(Str.replace('l', 'D'));    } }OutputReturn Value :WelcTme tT TutTrialspTint.cTm Return Value :WeDcome to TutoriaDspoint.com

Following example shows how to remove a character from a particular position from a string with the help of removeCharAt(string, position) method.ExampleLive Demopublic class Sample {    public static void main(String args[]) {       String str = "this is Java";       System.out.println(removeCharAt(str, 3));    }    public static String removeCharAt(String s, int pos) {       return s.substring(0, pos) + s.substring(pos + 1);    } }Outputthis is Java

The hasMoreTokens() method is used to test if there are more tokens available from this tokenizer's string.ExampleLive Demoimport java.util.*; public class StringTokenizerDemo {    public static void main(String[] args) {       // creating string tokenizer       StringTokenizer st = new StringTokenizer("Come to learn");       // checking elements       while (st.hasMoreElements()) {          System.out.println("Next element : " + st.nextElement());       }    } }OutputNext element : Come Next element : to Next element : learn