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Variables

Fundamentals

Variables, sometimes called properties, are a core concept of programming. Similar to variables in math, you use variables in programming to store values. This allows you to reference them later.

In Java, variables have a few different parts:

  • Type: the variable's type
  • Name: a descriptive variable name
  • Value: the variable's value

Below is a variable:

String myName = "Cody Winton";
  • Type: String
  • Name: myName
  • Value: "Cody Winton"

Finally, the line of code is terminated with a semicolon: ;.

Strong and Static Typing

Java is a strongly, statically typed language, meaning that every variable has a type at compile time and you can't a variable's type after it has been set, though you can change its value.

Java requires explicit typing for any variable. Let's see this in action as we define a few String variables:

String aString = "This is a String value";
String aVal = "Can be 123 or @ or # or any other characters!"; // Testing

aVal = "Testing val"; // The value of a variable can be changed

// This below would fail. 123 is not a string, since it is not surrounded by quotes
aVal = 123; // fails

// You can also set the value after creating the variable
String newVal;
newVal = "Testing new val";