Why is it not possible to implement the multiple inheritance in Java? How do you solve that problem?

I need help with this Java program. I got some minor error that I couldn't fix. Checker Classes You will have to implement specific checks to highlight errors found in the source files. We provided an interface Check.java that defines a single method public Optional<Error> lint(String line, int lineNumber) . All the checkers you write should implement this interface and hence, you need to implement the lint method. All of these should return an an Error when one is present with a custom message of your choosing to describe what the error means to the user. If the condition a Check is looking for is not present for a line, should return Optional.empty(). Other class Error.java public Error(int code, int lineNumber, String message) Constructs an Error given the error code, line number and a message. public String toString() Returns a String representation of the error with the line number, error code and message. The representation should be formatted as (replace curly braces with…

Using Java. Enhance the invoice-printing program by providing for two kinds of line items: One kind describes products that are purchased in certain numerical quantities (such as “3 toasters”), another describes a fixed charge (such as “shipping: $5.00”). Hint: Use inheritance. I've seen this question asked before, however, the code is very confusing to me.

Please write a Java program with at least two classes. Use a circle to represent it! The class should have at least one non-static setter method and one non-static getter. Implement at least one method test that invokes the setter method and the corresponding getter method so that the value out == the value in!

I need help with this Java program. I got some minor error that I couldn't fix. Checker Classes You will have to implement specific checks to highlight errors found in the source files. We provided an interface Check.java that defines a single method public Optional<Error> lint(String line, int lineNumber) . All the checkers you write should implement this interface and hence, you need to implement the lint method. All of these should return an an Error when one is present with a custom message of your choosing to describe what the error means to the user. If the condition a Check is looking for is not present for a line, should return Optional.empty(). Other class Error.java public Error(int code, int lineNumber, String message) Constructs an Error given the error code, line number and a message. public String toString() Returns a String representation of the error with the line number, error code and message. The representation should be formatted as (replace curly braces with…

Create the UML Diagram for this java code import java.util.Scanner; interface Positive{    void Number();} class Square implements Positive{    public void Number() {        Scanner in=new Scanner(System.in);        System.out.println("Enter a number: ");        int a = in.nextInt();            if(a>0) {                System.out.println("Positive number");            }            else {                System.out.println("Negative number");            }            System.out.println("\nThe square of " + a +" is " + a*a);            System.out.println("\nThe cubic of "+ a + " is "+ a*a*a);    }} class Sum implements Positive{    public void Number() {        Scanner in = new Scanner(System.in);            System.out.println("\nEnter the value for a: ");            int a = in.nextInt();            System.out.println("Enter the value for b" );            int b= in.nextInt();            System.out.printf("The Difference of two numbers: %d\n", a-b);            System.out.printf("The…

Still referencing Java, (I hope this is how follow-up questions work, you know my previous question) how could method overloading help reduce errors and are method overloads a top-down or bottom-up approach? Or, is there a difference between top-down and bottom-up in consideration to overloading methods vs writing the actual program?

Please solve this in java, using the Gui system(Jframe, Jpanel, etc) from java, not java fx thanks.

Use the Eclipse IDE to write java code for Functionality for the “Doctor” interface: The system should allow a doctor to assign a new doctor to a patient using the list of all doctors. The system should then send confirmation messages to the patient and both doctors The appearance of the interface is not important as long as the required functionality is provided. That is, you are not expected to implement a fancy looking interface. just ensure it has a home button and a log out button

In java, implement a simple email messaging system. a message has a recipient, a sender, and a message text. a mailbox can store messages. supply a number of mailboxes for different users and a user interface for the user to login, send messages to other users, read their own messages, and log out. Given the code I have so far, what needs to be added? class Message {     private String sender;     private String recipient;     private String messageText;       public Message(String sender, String recipient) {         this.sender = sender;         this.recipient = recipient;         this.messageText = " ";     }       public void append(String text) {         this.messageText += text;     }       public String toString() {         return "From: " + sender + "  To: " + recipient + "\n" + this.messageText;       } }   class Mailbox {     private ArrayList<Message> email;       public Mailbox() {         this.email = new ArrayList<Message>();     }       public Message…