Key Concepts

Review core concepts you need to learn to master this subject

length() String Method in Java

concat() String Method in Java

String Method equals() in Java

indexOf() String Method in Java

charAt() String Method in Java

toUpperCase() and toLowerCase() String Methods

length() String Method in Java 

String str = "Codecademy";  

System.out.println(str.length());
// prints 10

In Java, the length() string method returns the total number of characters – the length – of a String.

String Methods
Lesson 1 of 1
  1. 1
    Introduction to String Methods
    As you may recall, a String, which is widely used in Java, is an object that represents a sequence of characters. It is a great way to store information. Because character strings are so vital to…
    Start
  2. 2
    length()
    In Java, the length() string method returns the length ⁠— total number of characters ⁠— of a String. Suppose we have a String called str, str.length() would return its length. Take a look at this…
    Start
  3. 3
    concat()
    The concat() method concatenates one string to the end of another string. Concatenation is the operation of joining two strings together. Suppose we have a String called str1 and another String ca…
    Start
  4. 4
    equals()
    With objects, such as Strings, we can’t use the primitive equality operator == to check for equality between two strings. To test equality with strings, we use a built-in method called equals(). F…
    Start
  5. 5
    indexOf()
    If we want to know the index of the first occurence of a character in a string, we can use the indexOf() method on a string. Remember that the indices in Java start with 0: String letters = “ABCD…
    Start
  6. 6
    charAt()
    The charAt() method returns the character located at a String’s specified index. For example: String str = “qwer”; System.out.println(str.charAt(2)); It would output e because that’s what’s at…
    Start
  7. 7
    substring()
    There may be times when we only want a part of a string. In such cases, we may want to extract a substring from a string. The substring() method does exactly that. For example: String line = “…
    Start
  8. 8
    toUpperCase() / toLowerCase()
    There will be times when we have a word in a case other than what we need it in. Luckily, Java has a couple String methods to help us out: - toUpperCase(): returns the string value converted to up…
    Start
  9. 9
    Review
    Congratulations! 🙌 We have learned some of the string methods that come with the String class: - length() - concat() - indexOf() - charAt() - equals() / equalsIgnoreCase() - substring() - toUppe…
    Start

What you'll create

Portfolio projects that showcase your new skills

Pro Logo

How you'll master it

Stress-test your knowledge with quizzes that help commit syntax to memory

Pro Logo