Which of these method of class string is used to extract a substring from a string object in Java?

String is one of the widely used java classes. The Java String class is used to represent the character strings. All String literals in Java programs are implemented as instance of the String Class. Strings are constants and their values cannot be changed after they created. Java String objects are immutable and they can be shared. The String Class includes several methods to edit the content of string.

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• Exception Throws
• Internal implementation substring(int beginIndex)
• Internal implementation substring(int beginIndex, int endIndex)
• Java String substring() method example
• Java String substring() Method Example 2
• Applications of substring() Method
• Which methods are used to extract the characters from string?
• Which method is used to extract a single character from a string in Java?
• Which of the following method extracts a part of a string from a string object?
• Which method is used to extract a single character at an index?

Creating a String Object:

A String object can be created as

String Str=”Car Insurance”;

The string object can also be created using the new operator as

String str= new String(“Car Insurance”);

Java provides a special character plus (+) to concatenate strings. The plus operator is the only operator which is overloaded in java. String concatenation is implemented through the String Builder of String Buffer class and their append method.

Examples of Java String Class:

1. Finding the length of the string

The length() method can be used to find the length of the string.

String str = "Car insurance"
System.out.println(str.length());

2. Comparing strings

The equals() method is used to comapre two strings.

String str = "car finance";
if ( str.equals("car loan") )
{ 
  System.out.println("Strings are equal"); 
}
else
{
  System.out.println("Strings are not equal");
}

3. Comparing strings by ignoring case

The equalsIgnoreCase() method is used to compare two strings by ignoring the case.

String str = "insurance";
if ( str.equalsIgnoreCase("INSURANCE") )
{ 
  System.out.println("insurance strings are equal"); 
}
else
{
  System.out.println("insurance Strings are not equal");
}

4. Finding which string is greater

The CompareTo() method compares two strings to find which string is alphabetically greater.

String str = "car finance";
if ( str.CompareTo("auto finance") > 0)
{ 
  System.out.println("car finance string is alphabetically greater"); 
}
else
{
  System.out.println("car finance string is alphabetically lesser");
}

5. Finding which string is greater while ignoring the case.

The compareToIgnoreCase() method is same as the CompareTo() method except that it ignores case while comparing.

String str = "car finance";
if ( str.compareToIgnoreCase("CAR finance") = 0)
{ 
  System.out.println("strings are alphabetically same"); 
}
else
{
  System.out.println("strings are alphabetically not same");
}

6. Position of a string in another string.

The indexOf() method is used to find the position of a string in another string.

String str= "car insurance";
System.out.println( str.indexOf("car") );

7. Extract single character from a string.

The CharAt() method is used to extract a single character by specifying the position of the character.

String str = "Auto Finance";
System.out.println( str.charAt(5) );

8. Extracting part of a string.

The substring() is used to method part of a string by specifying the start position and end position.

String str = "Car Finance";
System.out.println( str.substring(1,3));

9. Hash code of a string.

The hashCode() method is used to get the hash code of a string.

String str = "Auto Insurance";
System.out.println(str.hashCode());

10. replacing characters in a string.

The replace() method is used to replace a character in a string with new character.

string str = "Auto Loan";
System.out.println(str.replace("A", "L"));

11. Converting a string to upper case.

The toUpperCase() method is used to convert a string to upper case letters.

String str = "Cheap Car Insurance";
System.out.println(str.toUpperCase());

12. Converting a string to lower case.

The toLowerCase() method is used to covert a string to lower case letters.

String str = "Insurance Quote";
System.out.println(str.toLowerCase());

Recommended Reading:

Java HashMap Class Example

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