So the first thing we did was make a program called memory calculator. now we are supposed to make a sub class that modifies the program to also do exponents and natural logs. Then to make a new class that acts as the driver for what is now called the scientific memory calculator which includes the exponent and log. I have watched this through debug and im a little confused. first off it creates a variable for currentValue in current and in sci which are my instances, which i dont think is what i really want to do, I am unsure how to get the things in the Scientificmemcalc to do stuff without calling them directly. so when i try to do the power feature it does everything correct but it sets the sci current value to the correct answer, and now i cant figure out how to pass it on to the current current value.
This is the memory calculator :
public class MemoryCalculator {
public static void main(String[] args) {
MemoryCalculator current = new MemoryCalculator();//creates an instance
int choice = 0;
do{//main loop
System.out.println("Current value: " + current.getCurrentValue() + "
I created a superclass Ships and under that a class CivilShips. Under that HumanBulkFreighter.
I declared variables in Ships and CivilShips and wanted to have them set in HBF to a specific value. When I know try to compile them I get the following:
how to get access from variables in a super class or a subclass. Here is what I got:
1) I have a super class that is in Jar file, I created a link in Eclipse, I know that the link is created correctly, I am going to concentrate just in one variable, so I don’t have to put all the code here firstName; in the super class(the one that is define in the path)
public class CommissionEmployee { // Field descriptor #6 Ljava/lang/String; private java.lang.String firstName;
Assuming that we have two classes B and C which inherit from class A. What is the best way to pass a parameter from an object of class B to an object of class C by the use of class A without using static variable and without defining a get function in B?
I enter a value in the text box in one class and want to pass that value to another class in order to compare it and color the cell in a table. In the first class I have
It just wont work... Everytime I try to pass a variable into a class it sets it to 0. What to do.
The variable should be '2', but it prints out as 0!?
Java Code: package Zoo; import java.util.Random; public class Animal { Random random = new Random(); public void Eat(){ System.out.println("The animal starts to eat.");
[Code]...
The method bash, needs the variable 'playerTwo' to be 2, to carry on. But it prints out 0.
Int the animal constructor, I passed in the variable from another class, and it prints out 2 in the constructor like it should. But outside of the constructor it is equal to 0.
I am trying to get the username and password for one class and send them to another. However I cannot send them in the constructor because a database class is getting them and I need that constructor blank. However if I do not pass the class in the constructor I get a NULL error, even better when I do pass it in I seem to get a thread lock. I do try to do my own housekeeping and close the one frame before I open a new one but it doesn't work. I will do my best to show the design of the program.
program starts Java Code: public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { // connects to database and generates a GUI new UserPromptScreen();
[code]....
I have to pass in UserPromptScreen in for it to work. This will cause me issues later with my design.
I want to put this code in a class then call it in another class , but i do not how to do that. This code is working fine in my main class , but i want to write this code to another class for call it in main class.
I'm getting this error, I definitely know that is my error trying to pass method/variable because when I commented received part of my code it ran and worked.
I get this error
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)
I am having trouble taking user input and passing it to another class as a variable. If I assign the value explicitly (see line 59), it works just fine. What I want to do though, is assign the input from inputField to the variable inputVariable. I tried using:
inputVariable = inputField.getText();
This does not work. Regardless of what is typed into inputField, the output I get is just:
How do you declare methods for a class within the class whilst objects of the class are declared else where?
Say for instance, I have a main class Wall, and another class called Clock, and because they are both GUI based, I want to put a Clock on the Wall, so I have declared an instance object of Clock in the Wall class (Wall extends JFrame, and Clock extends JPanel).
I now want to have methods such as setClock, resetClock in the Clock class, but im having trouble in being able to refer to the Clock object thats been declared in the Wall class.
Is this possible? Or am I trying to do something thats not possible? Or maybe I've missed something really obvious?
Regarding the lifecycle of servlet , in headfirst servlet i can find :
You normally will NOT override the service() method, so the one from HttpServlet will run. The service() method figures out which HTTP method (GET, POST, etc.) is in the request, and invokes the matching doGet() or doPost() method. The doGet() and doPost() inside HttpServlet don’t do anything, so you have to override one or both. This thread dies (or is put back in a Container-managed pool) when service() completes.
How can I call the doGet method of the subclass from the superclass. i am not getting this .
I have a quick polymorphism question. I have a parent class and a sub class that extends the parent class. I then declare an array of parent class but instantiate an index to the sub class using polymorphism. Do I have to have all the same methods in the child class that I do in the parent class? Here is an example of what I mean.
public class ParentClass { public ParentClass(....){ } public String doSomething(){ } } public class ChildClass extends ParentClass { public ChildClass(....)
[Code] ....
Is polymorphism similar to interfaces where the child class needs all the same methods?
I want to know is there any way we can call parent class method using child class object without using super keyword in class B in the following program like we can do in c++ by using scoop resolution operator
class A{ public void hello(){ System.out.println("hello"); } } class B extends A{ public void hello(){ //super.hello(); System.out.println("hello1");
i want to write a class in such a way that i should get the current execution time of another class which is running. I searched in net but it shows only how to calculate the time duration of the current class which is running. But as per my way, i need the execution time of one class from another class. How to do this ?
I am working on a program that simulates a bug moving along a horizontal line, My code works correctly when I test it in it's own class but when I tried testing my constructor and methods in a test class I received an error saying, "package stinkBug does not exist" on lines with my methods. However, stinkbug is not a package.
Java Code:
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */
How to create object for "class B" and call the "function_B" from other different class D where class D has no connection with class A? Here is my program.
public class A(){ void print(){} } class B{ void function_B(){} } class C{ void function_C(){} }
Here, A, B, C are in the same package. But class D is in different package.
I am a beginner here at JAVA and I am trying to program a Gratuity Calculator using both interface class and object class but it keeps on compiling with errors saying "cannot find symbol".I tried everything to fix it but it just keeps on stating symbol.
[CODE] public class GratuityCalculator extends JFrame { /* declarations */
// color objects Color black = new Color(0, 0, 0); Color white = new Color(255, 255, 255); Color light_gray = new Color(192, 192, 192);
