1. The String type
The String type is one of the most used types in Java. It just might be the most used type. There's a reason why it is so popular: such variables let you store text — and who doesn't want to do that? Additionally, unlike the int and double types, you can call methods on objects of the String type, and these methods do some useful and interesting things.
What's more, all Java objects (all of them!) can be transformed into a String. Well, to be more precise, all Java objects can return a text (string) representation of themselves. The name of the String type starts with a capital letter, because it is a full-fledged class.
We'll return to this type more than once (it is super useful and interesting), but today we will make a brief introduction.
2. Creating String variables
The String type is designed for storing strings (text). To create a variable in code that can store text, you need to use a statement like this:
String name;
String variable
Where name is the name of the variable.
Examples:
| Statement | Description |
|---|---|
|
A string variable named name is created |
|
A string variable named message is created |
|
A string variable named text is created |
Just as with the int and double types, you can use the shorthand notation to create multiple String variables:
String name1, name2, name3;
String variables
3. Assigning values to String variables
To put a value into a String variable, you need to this statement:
name = "value";
String variable
And now we have come upon the first difference between this type and those we have already studied. All values of the String type are strings of text and must be enclosed in double quotes.
Examples:
| Statement | Note |
|---|---|
|
The name variable contains the text Steve |
|
The city variable contains the text New York |
|
The message variable contains the text Hello! |
4. Initializing String variables
As with the int and double types, variables of the String type can be initialized immediately when they are created. In fact, this is something you can do with all types in Java. So we won't mention it anymore.
String name1 = "value1", name2 = "value2", name3 = "value3";
String name = "Steve", city = "New York", message = "Hello!";
The Java compiler will complain if you declare a variable without assigning any value to it and then try to use it.
This code won't work:
| Statement | Note |
|---|---|
|
The name variable is not initialized. The program won't compile. |
|
The a variable is not initialized. The program won't compile. |
|
The x variable is not initialized. The program won't compile. |
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