How do I call a class within the main. For example, this is what i have in my code right now. I am trying to call the class BlackJackGame.
package blackjack
public class BlackJack {
public BlackJack() {
BlackJackGame();
}
}
The idea is to create a program to add plants and retrieve plants from a Nursery. I created a class with the properties of the plants and also there is the class an Array list to keep track of the plants entered ( they will have to be printed later) (I am not too sure if adding a public class there is the best option.
The program will allow the user to pick and action and from there the code will do something. I don't want to have all the code inside 'main' The problem is in line 114.This is what I have so far.
Java Code:
package plant.nursery;
import java.util.ArrayList;
import java.util.Scanner;
/**Class to create a plant for a nursery.
public class PlantNursery
[code]....
I'm trying to call a method to my main method, but I can't seem to get it to work and it keeps resulting in a compile error.
import java.io.*;
import java.awt.Point;
import java.text.DecimalFormat;
import java.util.Random;
public class Chase {
public static void main(String args[]){
[Code] .....
I have been reading about methods and I do have a beginner level understanding on how they work. I was trying to mess around and make a dog calculator using methods. I ran into a small snag; I cannot get the method to call to the main or the program to compile correctly. The first code below is the original. To me it looks like (based off of some examples I looked at) there should be no problems, but NetBeans gives me a few errors. 1) line 8- "cannot find symbol, variable dogYearCalc; 2) line 18 illegal start of expression; and 3) line 22 - unreachable statement.
import javax.swing.JOptionPane;
public class KrisExample {
public static void main (String[] args) {
double dogYears = 0;
JOptionPane.showInputDialog (null,"Please enter you dog's age in human years:");
[Code] ....
Someone told me that I was calling dogYearCalc without any arguments in your main method. I take that to mean that I needed to add it to the main, so I did here:
public static void main (String[] args, double dogYearCalc) {
That got rid of my first error, but then when I tried to run the program NetBeans said that I have no main class, so switched back to the original program above.
I thought that when I calling the dogYearCalc method on line 10 was the whole purpose of using a method. It seems to me that putting it somewhere in the main is counter productive.
Can we recall the main method? I'm trying a code to recall main method (after the calling of JVM). I know this doesn't make any sense but I'm trying this just like that.
Code:
class derived {
public static void main(String args[]) {
System.out.println("Main Method class");
show();
}
static void show()
[code]....
I can call a child method from a main method. If I have a parent called "Assessment", a child called "Quiz", and another child called "test". Can I instantiate an object like Assessment a = new test(); and call a method in test.
I know the method can be called if I instantiate the test t = new test() but that defeats the purpose of inheritance...
When I try to call an object it can't find the symbol in the argument list. NetBeans says that it cannot find the movieCategory symbol when I try to call it. When I compile it to test a popup comes up that states "One or more projects were compiled with errors. Application you are running may end unexpectedly. I ran it anyways and everything runs up to the point of where it should call the object.
At this point it should get the Movie object and run the code within that, but if I put one of the categories it throws. "Exception in thread "main" java. lang.RuntimeException: Uncompilable source code - Erroneous tree type: <any>at MovieApp.main(MovieApp.java:33)Java Result: 1"
From my understanding to call an object it requires objectName.methodName(argumentList). Here is my Main method
/**
*This application will store a list of 100 movies and display them by category
*/
import java.util.Scanner;
public class MovieApp
{
public static void main(String args[])
{
//Displays <code>String</code> welcome message
System.out.println("Welcome to the Movie Application.");
System.out.println("There are 100 movies in the list.");
System.out.println("What category are you interested in?");
System.out.println();
[code].....
This current one is to calculate a planes holding pattern. I have to write a method to prompt user to enter speed in knots, then it converts it to km/hr. Another method to calc. pattern width using the speed, another method to calc. pattern length, than a main method which would call and print out the speed in knots, speed in km, pattern width and length.My current problem is on the second method. It works in that I can enter the values and it gives me the correct answers, however it's asking me to enter the speed twice, instead of just once. Anything I try just results in errors and won't compile.
import java.util.Scanner ;
//main method
public class TitleRemoved {
public static void main(String[] args) {
double airSpeedKm = airSpeedOts () ;
System.out.println("That speed is " + airSpeedKm + " km/hr.") ;
[code].....
I want my code to not only work, but be organized and easily readable as well, so I want to avoid bad habits.
I have a frame which I want to load an applet inside it. Here is the code i have in my main method:
MyApplet myApplet = new MyApplet();
myApplet.init();
myApplet.start();
javax.swing.JFrame window = new javax.swing.JFrame("myApplet");
window.setContentPane(myApplet);
window.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
window.pack();
window.setVisible(true);
But I get an exception:
Quote
Exception in thread "main" java.lang.NullPointerException
at java.applet.Applet.getCodeBase(Applet.java:169)
at MyApplet.init(MyApplet.java:78)
at Intro.main(Intro.java:68)
Java Result: 1
Spoiler
import java.applet.*;
import java.awt.*;
public class JhonnyBravo extends Applet {
/**
*
* @param g
*/
@Override
public void paint(Graphics g) {
Color skin = new Color(241, 210, 169);
[Code] .....
I was reading the book, "Head First Java" and it was talking about how there may be multiple classes in a large application, but there will be only one main method.how does it work that way? How can you have multiple classes, but only one main method?
View Replies View RelatedHow should I call my findSmallest method in the main class.. Here is the code:
public class Tester {
public static void main(String[] args){
try {
BinaryTree<Integer> myTree2 = new BinaryTree<Integer>();
myTree2.insert(5);
myTree2.insert(2);
myTree2.insert(7);
[Code] ....
So the question is what kind of parameter I should pass in myTree2.findSmallest()??? Here is my findSmallest method..
public E findSmallest(Node<E> parent){
if(parent.left.left == null){
E returnValue = parent.left.data;
parent.left = parent.left.right;
return returnValue;
} else {
return findSmallest(parent.left);
}
}
I have looked over other people code relating to files that are related to my actual studies in class. My teacher hasn't worked on a lot of file problems so I want to gain some understanding on it.
1.) I have this class with variables declared
import java.io.*;
public class FileDisplay {
private String filename;
FileWriter outputfile;
File Inputfile;
I'm aware that having a private variable would not allow that variable to be accessed outside the code. Vice versa, public variable would do that. The FileWriter and the File Inputfile is something I don't understand, especially have them in classes. What is the purpose of them?
2.)
public class FileDisplay {
private String filename;
FileWriter outputfile;
File Inputfile;
[Code] ....
I have made this code here that opens the output and input file. If I make another method, how would I display the text onto that same file. Hard to clarify for me, but in each method do I just keep creating :
FileWriter outputfile=new Filewriter(filename)
I use Eclipse IDE
public class Emp {
private String name;
private String jobTitle;
public void setName(String nameIn){
name=nameIn;
[Code] ....
<terminated> TestClass
Exception in thread "main" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Unknown Source)
at TestClass.payOneEmp(TestClass.java:21)
at TestClass.main(TestClass.java:13)
// Add range to Vehicle.
class Vehicle {
int passengers; // number of passengers
int fuelcap; // fuel capacity in gallons
int mpg; // fuel consumption in miles per gallon
// Display the range.
void range() {
System.out.println("Range is " + fuelcap * mpg);
[Code] ....
I'm compiling it in Eclipse and this continues to show in the console display
Minivan can carry 7. Exception in thread "main" java.lang.NoSuchMethodError: Vehicle.range()V
at AddMeth.main(AddMeth.java:34)
package Experimentation;
import javax.swing.*;
import java.awt.event.*;
public class SimpleGUI1B implements ActionListener {
JButton button;
public static void main(String[] args) {
SimpleGUI1B gui = new SimpleGUI1B();
gui.go();
[code]...
This is a program from Head First Java! since main is static it shouldn't be able to call non-static methods because statics do not use any instance variable values but in the above program we're call a non-static method go() how is it possible?
How do you call classes within other classes? Or can you only call classes through the main?
View Replies View RelatedI'm doing an aggregation exercise that's suppose to find the volume and surface area of a cylinder. What I'm trying to do is pass values from one class, to a second class, and that second class passes values to a third class.
This may be a clearer explanation: The first class is the main program which sends values to the second and third class. The second class is used do calculations for a circle (a pre-existing class from another assignment). The third class grabs the values that the second class calculated and calculates those values with the one that was passed from the first class to the third class. The first class then prints the outcome.
Problem is when the program gets to the third class, it just calculates the value from the first class with the default constructor from the second class. It's like the second class never received the values from the first class. I think I'm missing a step, but I don't what it is.
First Class:
package circle;
import java.util.Scanner;
public class CylinderInput
{
static Scanner in = new Scanner(System.in);
public static void main(String[] args)
{
//user defined variable
[Code]...
what is different between void main() and public void main()
View Replies View RelatedSo heres the code for one of my classes..
import java.awt.*;
import javax.swing.*;
public class Splash extends JPanel {
public void paint (Graphics g)
[code]....
Now, when i call it from a different class in the main method, like this:
new Splash();
i am creating a desktop application. In this application, firstly there is a log in form. Now, i want to display the another form on the same window i.e by removing log in form a new form..
View Replies View RelatedUsing JPA 2.1, I have been trying without luck to call a function that returns a REF CURSOR containing RECORD TYPES. Is there a way of doing this?
One Example of trying:
Query query = em.createNativeQuery("select my_package.my_function from dual");
Object a = query.getSingleResult();
I have also tried to use the StoredProcedureQuery though this does not look like it can return the functions value.
Produced
org.springframework.orm.jpa.JpaSystemException: No Dialect mapping for JDBC type: -10;
nested exception is org.hibernate.MappingException: No Dialect mapping for JDBC type: -10
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:244)
[Code] ....
I am calling a jsp page from my servlet using the requestdispatcher.forward(myjsp.jsp) method. myjsp.jsp is creating a new thread which is parallely processing along with the servlet. The issue is that the jsp page is not displayed until the servlet finishes its execution, although the new thread is created by jsp and is executing in parallel. How do we have the jsp page displayed even when the servlet is executing.
View Replies View RelatedI just wanted to ask that when we invoke a function by passing certain arguments in it ,so for instance I have certain variables like a,b and c with some values assigned to them,so when I invoke a function like func(a*b , 8, c+a) where the function func accepts parameters like func(int x,int y,int z) ,so is there any order of evaluation of expressions defined like the value of c+d would be evaluated first and then assigned to variable z ,because in C we have sequence points and since comma when acting like a separator is not a sequence point so any of the expression can be executed first ,so basically is there any sequence in which the function arguments are assigned to the parameters of the function or any relation with the stack implementation.
Even in C ,the printf starts executing its expressions from right to left so basically in why does it happen there when comma is a separator in a function argument.
I need to get the string encodedString from the method encode able to be used in the decode method.
Java Code:
public String encode(String plainText) {
int prepareString;
int shiftChar;
String preparedString2 = prepareString(plainText);
String encodedString = "";
for(int c = 0 ; c < preparedString2.length();c++)
[Code] ....
I have a line code like this one:
String result = someHeavyMethod();
and I need to add this logic: "if the method doesn't finish within 10 seconds, cancel it and let me continue with the rest of the program".