How to change the font size of context menu?

Error: non-static variable this cannot be referenced from a static context?

• I am writing a Java GUI and I want to change the panel however when calling the GUI from the main function I get the error "error: non-static variable this cannot be referenced from a static context" when trying to make a new instance of my object on in case 1: import java.awt.*; import javax.swing.*; import java.util.*; public class addModify { //JPanels declared here JPanel airplanePane, airportPane, runwayPane, fuelPane; JFrame newFrame = new JFrame(); public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("Hay"); String[] list = {"Airplane 1", "Airport 2", "Runway 3", "Fuel 4"}; for(int i = 0; i < 4; i++) { System.out.println(list[i]); } System.out.println("Please enter a menu option:"); int newInteger = input.nextInt(); switch(newInteger) { case 1: mainMenu test = new mainMenu("Hello", 500, 500); break; case 2: System.out.println("Ello2"); break; case 3: System.out.println("Ello3"); break; case 4: System.out.println("Ello4"); break; default: System.out.println("Default"); break; } } class mainMenu { public mainMenu(String title) { this(title, 500, 500); } //Constructor for title and width public mainMenu(String title, int w) { this(title, w, 500); } //Constructor for title, width, and height public mainMenu(String title, int w, int h) { newFrame.setTitle(title); newFrame.setSize(w,h); newFrame.setVisible(true); newFrame.setResizable(false); newFrame.add(airplanePane); } } class addAirplane { public addAirplane(String title) { airplanePane = new JPanel(); airplanePane.setLayout(new GridLayout(6,2)); JLabel newLabel; JTextField textArea; newLabel = new JLabel("Make"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); newLabel = new JLabel("Model"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); newLabel = new JLabel("Fuel Tank Size"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); newLabel = new JLabel("Fuel Burn Rate"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); newLabel = new JLabel("Fuel Type"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); newLabel = new JLabel("Airspeed"); airplanePane.add(newLabel); textArea = new JTextField(10); airplanePane.add(textArea); } } }

• Answer:

  I don't see where you're trying to create a new instance of your addModify class. Maybe you plan to do this later? For now, you'll get close to working if you declare the JPanels and the JFrame as static so they will be accessible from main(). You also need to make the nested classes mainMenu and addAirplane static too, as in: static class mainMenu ... static class addAirplane ... Otherwise, they are "inner classes" that have to be associated with an instance of the surrounding class...but there isn't any instance of addModify. By the way, these are odd classnames for Java. Conventionally, the class name begins with a capital letter (mixed case), while member names (except for the constructors) begin with a lowercase letter and capitalize the inner words ("camel" case...because of the "humps" in the middle.