Java Java intro
  1. Java intro
  2. Java basics
Java core
  1. Java variables
  2. Java conditionals
  3. Java loops
  4. Java arrays
  5. Java strings
Object-oriented Java
  1. Java OOP 1
  2. Java OOP 2
  3. Java packages
  4. Java interfaces
Java interactive
  1. Java user input
  2. Java exceptions
  3. Java events
Graphical Java
  1. Java GUI
  2. Java GUI layout
  3. Java graphics
Java extras
  1. Java applets
  2. Java sounds
  3. Java random numbers
Java wrap-up
  1. Java summary

Java strings

A string is a grouping of text. You can store this group of a text in a variable that would then be known as a String variable. You can print strings, and you can also use various functions to perform operations on strings such as returning the string's length.

This tutorial focuses on:

Declaring a string

Syntax:
String nameOfString = "stringValue"; String nameOfString = new String("stringValue");
Example:
String aString = "This is a string"; String aString = new String("This is a string");

Whether you declare a string as a variable or with the new keyword, it becomes an instance of the String class. We discuss classes in detail in the Object-oriented Java page. For now, you should just know that a class is a special type of variable.

Printing a string

Use the System.out.print or System.out.println methods to print a string.

Example:
String myString = "I like pineapple"; //print a string variable System.out.println(myString); //print a non-variable string //just put some text in double quotes and it's done System.out.println("Green is a great color");
Output:
I like pineapple Green is a great color

Concatenation

Concatenation is the process by which two or more strings are joined together. This is achieved with the use of the + operator. You can use concatenation to join two or more strings into one or print two or more strings together.

Example:
String aString = "Here is some text. "; String anotherString = "Here is some more text."; //declare a third string and //combine into it the first two strings String combinedString = aString + anotherString; System.out.println(combinedString); //print two strings together System.out.println("Notepad is a " + "simple text editor.");
Output:
Here is some text. Here is some more text. Notepad is a simple text editor.

String functions

The String class has various functions (methods) you can use to work with text.

Example:
String aString = "Here is some text"; String anotherString = "Here is some more text"; //extract the third character //from the aString string and print it System.out.println(aString.charAt(2)); //compare the two strings aString and anotherString //and specify if they are the same or not System.out.println("The two strings match: " + aString.equals(anotherString)); //print the length of the aString string System.out.println("The length of the aString string variable is " + aString.length()); //print the anotherString string in all uppercase letters System.out.println(aString.toUpperCase());
Output:
r The two strings match: false The length of the aString string variable is 17 HERE IS SOME TEXT
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