class Base
{
public Base rtc() {
System.out.println("am in parent");
return new Base();
}
}
class Ret extends Base
[Code] ....
Output :
I am in child class but b1.rtc requires b2 to hold the return value y not Ret's object.
Alright, I don't understand how to link my compress method to my return statement method "getPText". Also in my compression I only want it to compress for 3 or more consecutive letters.
import java.util.Scanner;
class RunLengthCode {
String pText;
String cText;
void setPText(String PText) {
pText = "";
}
[Code]...
Im having trouble with my method return. I am new to using methods and cant seem to grasp the idea on the return part. I have to write a method that tells if a number is prime or not. This is what I have so far and it wont compile because it is saying "missing return statement } "..
import javax.swing.JOptionPane;
public class IsPrimeMethod
{
public static void main(String []args)
{
String primeNum;
int number;
int i = 2;
[code]....
I have two classes (Daughter and Son) that contain some very similar method definitions:
public class Family {
public static void main(String[] args) {
Daughter d = new Daughter();
Son s = new Son();
d.speak();
s.speak();
[Code] .....
Each of those classes has a "speak" method with two out of three lines being identical. I could move those into a parent class, but I need each of the child classes to continue to exhibit its unique behavior. I'm trying the approach below, which replaces the unique code with a call to a "placeholder" method that must be implemented by each child class:
public class Family {
public static void main(String[] args) {
Daughter d = new Daughter();
Son s = new Son();
[Code] .....
This works and moves the shared code from two places (the Daughter and Son classes) into one place (the new Mother class, which is now a parent class of Daughter and Son). Something about this feels a bit odd to me, though. It's one thing for a child class to override a parent class's methods to extend or alter their behavior. But, here, I've implemented an abstract method in the parent class to alter what happens when the parent class's method (speak(), in this case) is called, without overriding that parent class method itself.
I want to use a method, which takes for example an int and also returns an integer. For example, if the the given integer is strong return a, if it is notstrong return b. How would you write that in a Code?
I want to use that in a more general way. I want to give a method mlong the value X of the type date and let it return an int. Type date consists of 3 int, one of them is the int month.
mlong should return an int depending on the X.moth. at the moment my code looks like this:
// File1:
public class date {
public int day;
public int month;
public int year;
}
// File 2:
public class monthlength {
public int mlong(date X) {
int t;
t = X.month;
if (t == 1 || t == 3 || t == 5 || t == 7 || t == 8 || t == 10 || t == 12)
{ return 31; }
if(t == 4 || t == 6 || t == 9 || t == 11)
{return 30;}
}
}
class One
{
public static void doStuff()
{
System.out.println("One");
}
}
class Two extends One
[code]....
My understanding of static says that static methods cannot be overrriden but the compilation of the above code results in Overriding rule violation error.
For a few days I've been reading about the importance of overriding the equals method. How overriding it actually determines or checks the values stored in the variable. I realize that you can check the values stored in the primitive datatypes with "==", and when you don't override the equals method it acts the same way, right? When used with a reference datatype, "==" or the default equals() method only compares, or sees, if the variable is pointing to the same instance of a class. For some reason, in the examples, what is taking place to actually check the values stored inside the variables.
Here is part of an example (I've added comments for things that are confusing me):
@Override
public boolean equals(Object obj) {
//So we use Object here instead of the class type
// we're overriding this equals method for?
Is this so that we can use it to check different types? (overloading?)
if (obj == this) {
return true;
//Isn't this checking to see if the calling object is the same as the object we're passing to it?
Why doesn't this return false?
}
if (obj == null || obj.getClass() != this.getClass()) {
return false;
}
//How exactly do we check the values stored in each object though?
}
I am attempting to override the equals method from the Object class which checks if two variables point towards the same object. I want the method to check if if the argument being passed in(an object) has the same data(instance variables) as the object that's calling this method. A NullPointerException is being thrown; Here is the code.
package javaapplication5;
import java.text.NumberFormat;
import java.util.Scanner;
import java.lang.Object;
public class Product {
private String product;
private String description;
private double price;
[Code] ....
And here is the stack trace
Exception in thread "main" java.lang.NullPointerException
at javaapplication5.Product.equals(Product.java:42)
at javaapplication5.Product.main(Product.java:24)
Java Result: 1
How do i print override the toString for WebBrowser as i would like to print out the object bc. Tested the program and it is fine if i put it in the main method rather than the WebBrowser constructor.
import java.util.*;
class ListNode <E> { /* data attributes */
private E element;
private ListNode <E> next;
/* constructors */
public ListNode(E item)
{ this(item, null);
[code]...
class SubB{
public void foo(){
System.out.println(" x");
}
}
public class X extends SubB {
public void foo() throws RuntimeException{
super.foo();
if(true) throw new RuntimeException();
System.out.println(" B");
}
public static void main(String [] args){
new X().foo();
}
}
Why the foo method of class X is not throwing a compile error because according to the override rule, if the superclass method has not declared exception, the subclass method can't declare a new exception...
How do i take input values for TwoDPoint (which are objects) and return it back in numerical values also print them.
When i create an object in main method and pass values to my function of return type TwoDPoint,it gives error:- found int,int need TwoDPoiint,TwoDPoint.
// Here is what i tried to do:
Created class TwoDPoint that contains two fields x, y which are of type int. Defined another class TestTwoDPoint, where a main method is defined.In the main method created two TwoDPoint objects.
Then I modified the class TestTwoDPoint and add another function to it. This function takes two TwoDPoints as input and returns the TwoDPoint that is farthest from the point (0,0).
Then I added another function to TestTwoDPoint. This function takes two TwoDPoints as input and returns a new TwoDPoint whose x value is the sum of x values of the input TwoDPoint's and whose y value is the sum of the y values of the input TwoDPoint's.
class TwoDPoint {
int x = 2;
int y = 4;
}
class TestTwoDPoint {
public static void main(String args[]) {
TwoDPoint obj1 = new TwoDPoint();
System.out.println(obj1.x);
System.out.println(obj1.y);
[Code] ....
What is the difference between two statements:
Class1 class1 = new Class();
class1 = Class2.method1();
and
Class1 class1 = Class2.method1();
I have one more query on the same lines ... I always need to call the method1 of Class2 whenever i create a object of class1. So I wanted to go with the constructor in Class1. But the method1 in Class2 has a return statement. so is there any better way to do this other than constructors.
Sample code:
public int class Class2{
public static method1(){
return 2;
}
}
public class Class1{
public Class1(){
Class2.method1();
}
}
This was an example of code that I'm trying to get to work, I swear I took it down just as it was written in class however mine says missing return statement....
Scanner keyb = new Scanner(System.in);
System.out.print("enter rows and columns");
int rows = keyb.nextInt();
int cols = keyb.nextInt();
int[] [] array = new int [rows] [cols];
printArray(array);
[code]....
My task is to make a mortgage calculator where the user selects which calculation they want the program to do via a menu. I got the menu to work and it keeps on looping until terminated so that's good. The starts when I want the user's choice (P, I or T) to be used in another method which will then execute another set of code (the calculation that needs to be done). I think passing parameters and return statements are what I need to use, but after reading and watching videos, I'm still not sure how to implement it into my program. For now, I want the user to input the letter "P" and then I want that information to be passed to the method, loanCalculator() where the if statement will make a decision to call the method, calcPayment and display the number 0 via the console. Once it can do that, I'll fill in the calculation methods with the proper code since I can at least navigate the user input to its associated calculator. It just keeps on looping the menu without going through the other methods.
import java.util.Scanner;
//Example of "big loop" in main to repeat using a No Trip (0,N) test first
public class Mortgage {
// constants
static double loanAmount;
static double interestRate;
static int term;
[code]....
consider this program :
public class hello {
/**
* @param args
*/
public static void main(String[] args) {
int s = new hello().h();
System.out.println(s);
} public int h(){
try{
int g = 10/0;
[Code] .....
the output is 7. how the flow is working. i understand that there is a divide by zero exception after which the control goes to catch. what about the return statement in catch . why is it overridden by finally..........
I am trying to compile the arguments program but it is giving missing return statement error. how to correct the error message.
public class Arguments {
public static Void main ( String args[])
{
int count, i=0;
String sdata;
[code]...
I am trying to understand the following code.This return statement should actually return the char at myArray[index] first, then increments the index afterwords correct?
Public char next(){
return myArray[index++];
}
Im trying to do this
if( 2/2 ) {
system.out.println( "number is not event" );
} else {
system.out.println( "number is event" );
}
However if statement requires a return of type boolean. So im forced to this instead
if( (2/2) != 0 ) {
system.out.println( "number is not event" );
} else {
system.out.println( "number is event" );
}
Is there a way to achieve the former method, without typecasting, if you had to typecast how do you do it?
I get an Sqlexecption with this message "com.microsoft.sqlserver.jdbc.SQLServerException: The statement did not return a result set."
When I execute this query :
...
Statement stmt = conn.createStatement();
stmt.executeUpdate("IF EXISTS (SELECT name FROM master.sys.databases WHERE name = N'Repository')
"
+ "PRINT 'Database exists'
[Code] .....
I want to create a database and a table in sql server if it doesn't exist. How can i prevent this error.
I'm attempting to format my doubles to two decimal places within my return statement. I have tried to use DecimalFormat but it gives me an error because my method needs to return a double and that results in a string being returned. I have also tried using the *100.00/100.00 method and that doesn't work when the number already ends in 0.
If I pass -150.00 it gives me -150.0 when I need two decimal places.
How can I go about doing this?
I am trying to override the equals method for my class TeamMember I have two fields:
private Details details;
private double salary;
Code for override I get an error on salary saying cannot invoke equals (double) on the primitive type (double)
Is their something I am missing/coding wrong?
Java Code:
public boolean equals(Object obj) {
//test exceptional cases
//avoid potential NullPointerException/ClassCastException
if ((obj == null) || (this.getClass() != obj.getClass()))
return false;
TeamMember other = (TeamMember) obj; //cast to a TeamMember object
// compare fields details and salary
return this.details.equals(other.details)
&& this.salary.equals(other.salary);
} mh_sh_highlight_all('java');
I have been assigned to write a program that has a user input random numbers then the program is to sort them in different ways. I have the coding for the different sorts but, I have an error saying that I am missing a return statement in the "Bubble" method. I am trying to return "arr[i]" in the "for loop" which gives me this error, and when I try to take the "return arr[i]" outside of the "for()" loop the error reads the it cannot locate variable "i".
import java.awt.* ;
import java.awt.event.*;
import javax.swing.*;
public class SwingSorts extends JFrame implements ActionListener
{
JRadioButton bubble;
JRadioButton selection;
[Code] .....
I'd like to know how to return a new array, I wrote in a method below the main method. I want to print the array but system.out.print doesn't work for arrays apparently. What structure i should use?
View Replies View RelatedI need to write a method that will consume string representation of Object type and will return one object of this type. How to set return type for the method in this case?
Here is exmaple :
public <?> identifyType(String typeString){
if (typesString.matches("String")){
return new String("");
}else if (typeString.matches("Integer")){
return new Integer(0);
}
//....etc..}
I stumbled upon a method that im not sure how to handle (yet).Below the code:
public DateTime() {
this.day = day(milliseconds);
this.month = month(milliseconds);
this.year = year(milliseconds);
this.hour = hour(milliseconds);
this.minute = minute(milliseconds);
[code]...
The two last methods stumped me. The return type to each is "DateTime", according to JUnit complaints.I know that I can use the "this" keyword to reference to the object. But how do I get these two methods to return the correct result?
I'm trying to calculate a certain value, but it is returning 0 and I'm not sure why. This is a measurement to define the angle from the equator and the center of the sun
public static double declination(int dayOfYear) {
double declination = asin((sin(23.45)*sin((360/365)*(dayOfYear - 81))));
System.out.println("dec " + declination);
return declination;
}