Static fields of the parent class should not be accessed through child class instances JAVA-W1030
Anti-pattern
10 months ago
—
10 months old
EXIT_ON_CLOSE should be accessed through WindowConstants, not JFrame
84 public GUI()
85 {
86 setResizable(false);
87 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 88 setBounds(100, 100, 305, 384);
89 contentPane = new JPanel();
90 contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));EXIT_ON_CLOSE should be accessed through WindowConstants, not JFrame
84 public GUI()
85 {
86 setResizable(false);
87 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 88 setBounds(100, 100, 305, 384);
89 contentPane = new JPanel();
90 contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
Description
Non-private static members of the parent class are accessible by child classes. However, it is a bad practice to do so, because it obscures where a value was actually declared. Always use only the declaring class to access static members.
Bad Practice
class SomeClass {
static Object staticData = null;
}
class SomeChildClass {
public void method() {
// Accessing the static value declared within the parent class through the child class.
SomeChildClass.staticData = this;
}
}
Recommended
class SomeChildClass {
public void method() {
// We are now accessing the static value through the parent class.
SomeClass.staticData = this;
}
}