String handling in java | Sharp Tutorial

Programming in Java

Object Oriented in Java

Advanced topics in Java

String Handling

In java, String is a predefined class that is final, so string objects are used and that may be the combination of array of characters. String variable is declared as following :

  String name="Sharp Tutorial"; // also known as string literals

We can also create string objects with the help of “new” keyword as following :

  String n= new String ("Welcome String");

If we use string literals, then in the following example ,

 String name="Sharp Tutorials";
 String name1="Sharp Tutorials"// here another instance not created as same string is present in string pool.

⇒ If we create two objects with new keyword, then two different objects are created.

Some important functions that may be called on String are as following :

1. equals(String s) :

This function compares if two string are equals or not.

3. length() :

This function returns the length of the string.

5. indexOf(char ch) :

This function returns the index of the given character.

7. trim() :

this function removes the leading and trailing whitespaces.

9. contains(String s) :

It returns true or false if a given string is found in the string.

2. equalsIgnoreCase(String s) :

This function also returns true or false and when comparing two strings, it ignores the case (upper/lower).

4. charAt(int index) :

This function returns the character at the given index.

6. lastIndexOf(char ch) :

This function returns the last index of the given character.

8. substring(int beginIndex, int lastIndex) :

This function cuts a portion of the String, if only one index is being passed, then the string is cut till the end from the given beginning Index.

10. toUpperCase(), toLowerCase() :

this function converts the string in upper case and lower case respectively.

String programm :

class StringExamples
{
  public static void main(String argsp[])
  {
    String name="Sharp Tutorials";
    System.out.println(name.equals("sharp tutorials"));
    System.out.println(name.equalsIgnoreCase("sharp tutorials"));
    System.out.println(name.length());
    System.out.println(name.charAt(2));
    System.out.println(name.indexOf('h'));
    System.out.println(name.substring(3));
    System.out.println(name.contains("tuts"));
    System.out.println(name.toUpperCase());
    System.out.println(name.toLowerCase());
  }
}

Output of the above program is as following :