Java Coursework Example | Topics and Well Written Essays - 1000 words

Java - Coursework Example The extends keyword indicates that the class is a child of class JFrame and represents an inheritance relationship. Implements keyword is essential while using an interface for it indicates that all the methods used in the interface must be declared with the signature declared in the interface declaration in this case ActionListener. The ActionListener implements event handling. We therefore go ahead and declare all the components of the form. Note that the programmer must be able to pre-visualize the desired form before putting down the code for creating it. Also it is worth noting that for neatness all the controls are placed within panels named Jpanel. Public static void main (String [] args) is the start point of every Java application of which every application must have one and only one method named main without which the application will not execute. The void keyword indicates that the application will not return any information. class ordermenu extends JFrame implements ActionListener declares a class that inherits from JFrame and implements ActionListener which detects user action such as clicking typing, pressing enter or any such action that the programmer my desire to capture. As in the other two classes we declare the controls we intend to place in the form such as JButton, JRadioButton, JTextField, JCheckBox, JComboBox and the JTextArea followed by variable declaration. public static void main(String[] args){ method constructs the required frame (form). The frame.pack()function causes the window to be resized to fit the preferred size by automatically adjusting its height and width. It is in this function that we now place all the controls that we had declared earlier in the desired position. As previously stated we place the controls within panels for better organization. Also note that since a panel is a container we can have panel within another panel. While adding controls into a panel, we use the add() function. Ideally every