Java For Dummies Quick Reference

Fields

A field is a variable that’s defined in the body of a class, outside any of the class’s methods. Fields, which are also called class variables, are available to all the methods of a class. In addition, if the field specifies the public keyword, the field is visible outside the class. If you don’t want the field to be visible outside the class, use the private keyword instead.

A field is defined the same as any other Java variable, but it can have a modifier that specifies whether the field is public or private. Here are some examples of public field declarations:

public int trajectory = 0;

public String name;

public Player player;

To create a private field, specify private instead of public:

private int x_position = 0;

private int y_position = 0;

private String error-message = “”;

Fields can also be declared as final:

public final int MAX_SCORE = 1000;

The value of a final field can’t be changed after it has been initialized. Note: Using capital letters in final field names is customary (but not required).