method called []getLetterGrades but the only hint My professor told me was that I needed to declare another array list for this method and he wouldnt tell me anything else so bummer. But I don't understand why if what we are returning is a char. It would make sense to return an array list of char to get letter grade. Which is what i did but since the function is a char, the array list character wont work as a return.Primarily i would like to know the type that is needed. I just want an explanation for an array list in this method and how it would serve in this method.
why interfaces are needed in Java,Now you saw what a class must do to avail itself of the s... - justpaste.it (if I paste the quote here, I get the "Page not found" error after posting -.^)
the first fragment reads that the compiler must be sure that a method exits at a compile time, whereas the second fragment denies it - if a[i] doesn't have the specified compareTo method, a JVM simply throws an exception.
Should we always use getters/setters, e.g. even in something like
Java Code:
class Foo { private static int foo; public int getFoo() { return foo; } public void setFoo(int fig) { foo = fig; } } mh_sh_highlight_all('java');
Or should we use the only when there is a good reason to use them, e.g. validation for a setter or may be computing a value to return from some variables etc. ?
I have a HTML page with an applet inside it.I have the applet class and all other needed classes in a jar file in jre/lib/ext folder (I'm on windows). But when I open the HTML file in a browser it gives me ClassNotFound exception..The HTML file is this:
I have this HostOnDemand class in its package in a jar file in jre/lib/ext but it can't be found.Since the applet is way too old, I'm using jre1.4.2 and netscape.
Let's say I'd like to print out something as a prompt without end with a new line char, so the standard System.out.println() is not an option and I'd like to find something else inplace of println().
Where to find that? I googled about that and learned printf() is the one I want, but how to get it from java api documentation.
I have a .jar that is installed in other computer(outside netbeans). Everything works fine except with report. I am sure the libraries needed for iReport is added in my lib folder but I receive this error message when I to load the report using the program.I use command prompt to see the error:
Java Code:
java -jar projCosting.jar mh_sh_highlight_all('java'); And here is the error message: Java Code: net.sf.jasperreports.engine.JRException: Error compiling report java source files : [b]D:CostingRptCosting_1288072391310_955208.java[/b] at net.sf.jasperreports.engine.design.JRJavacCompiler.compileClasses
[code]....
I have included the library in lib folder but do you think I have to install the iReport application?
The keys in a HashMap and the values in a Set must all be unique, but this can be circumvented when using custom objects in a HashMap and Set, because the compiler has no way to determine if the objects are equal or not, as shown in the example below:
Java Code:
import java.util.LinkedHashMap; import java.util.Map; public class HashCodeEquals { public void run(){ Person p1 = new Person(1, "John"); Person p2 = new Person(2, "Matt"); Person p3 = new Person(1, "John");
[code]....
Obviously the equals method is needed because that compares the two objects. But why is the hashCode method needed?
I have a simple classes here one is interface and another one is abstract class when i try to compile them abstract class is givving compilation error.
public interface MyInterface{ public void getName(); public void getName(String s); } public class HelloWorld{} abstract class SampleClass{
I have to meet certain requirements for this one program, and one of them is as follow: The program will require the user to enter the needed values one after another. If any of the entered values is invalid, then the program will detect that and go into a loop requiring the user to enter a valid value. The program must keep track of the total number of invalid values that the user has entered.
I know how to set a restriction and create a loop to keep asking the same question until it is satisfactory ( in this case I used a while loop) but I am at loss on how I should keep track of the total number of invalid values. I know I can use an increment but how do I set a variable for when the program meets an wrong input from the user.
I am creating a hangman game and I want to read in a list of words from a text file, but after the user inputs the name of the text file. I get 'Exception in thread "main" java.lang.NullPointerException'.
Here is the code, where I think the problems lie.
public void runModel(){ ArrayList<String> pirateWordsList = new ArrayList<String>(); System.out.println("What is the name of the file you would like to load? (The file included is called piratewords.txt'"); Scanner in=new Scanner(System.in); String file=in.next(); load(file);
[Code] ....
The full error message is this:
Exception in thread "main" java.lang.NullPointerException at uk.ac.aber.dcs.pirate_hangman.Model.load(Model.jav a:108) at uk.ac.aber.dcs.pirate_hangman.Model.runModel(Model .java:45) at uk.ac.aber.dcs.pirate_hangman.Main.main(Main.java: 6)
Im trying to create a program in which I read line by line the contents of a text file, and then report each letter along with its frequency. I was wondering how to read through the lines and process it so that my program knows to increase by a number each time a letter appears in my text file. For example, if A appears in my file 5 times, B 3 times, and C 0 times I want to eventually print out
A -- 5 B-- 3 C-- 0
My first thought was to do this using array lists but is there any way I could do this without using one?
Directions: public static void initialize(ArrayList names, ArrayList sores)
You should write a function that sorts both array lists, based on the values in the scores array list. This is one of the more conceptually challenging parts of the assignment. You want to sort the scores array list, and simultaneously alter the names array list so that the names continue to line up with their respective scores by index. In the example data above, when the score 9900 moves to the first element of the scores array list, the name "Kim" should also be moved to the top of the names array list. The function should have the following signature:
I'm having trouble figuring out how to sort the lists.
import java.util.ArrayList; import java.util.Scanner; public class Assignment5 { /** */ public static void main(String[]args) { intializeArrays();
I had to write a program that prompts the cashier to enter all prices and names, adds them to two arrays lists, calls the method that I implemented, and displays the result and use 0 as the sentinel value. I am having difficulty coming up with a for loop in the method, I believe I have the condition right but I am having trouble with the statements. I now know that String does not have the get property, but I have only done examples with integers and I am not very good with for loops and wouldn't know how to fix it.
public static void main(String[] args) { Scanner in = new Scanner(System.in); ArrayList<Double> sales = new ArrayList<Double>(); ArrayList<String> names = new ArrayList<String>(); System.out.print("Enter Number of Customers"); double salesAmount; System.out.print("Enter Sales for First Customers"); salesAmount = in.nextDouble(); while(salesAmount != 0)
I am stuck on this exercise and I don't know what exactly is wrong. I think it's something with the .remove and the for each loop, but I am not sure.
public class seven { public static void main(String[] args) { ArrayList<String> list = new ArrayList<String>(); list.add("aaa"); list.add("brr"); list.add("unni");
[Code] ....
This is what i get
Exception in thread "main" java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(Unknown Source) at java.util.ArrayList$Itr.next(Unknown Source) at seven.removeDuplicates(seven.java:24) at seven.main(seven.java:18)
private int coin; Money(int c) { coin = c; } int showCoin() { return coin; }
and for a test class, I need an array list with a couple of coins in it (i.e. ONE_POUND, TWO_POUNDS) and a loop that adds together the values of the coins in the list and prints the result. How can I do this?
I have this very simple application just to test console input:
import java.util.ArrayList; import java.util.Scanner; public class WriteTester {
[Code]....
When I let it run, only every third entry is put into the array list and I have to hit "enter" three times for the "break" in line 21 to trigger. I cannot find out why.
Im making a simple code to add an array to a List (the code im referring to is <String> )
import java.util.*; public class L5_ArrayListProgram { public static void main(String[] args){ String[] things = {"lasers","ghouls", "food", "dark"}; List<String>list1 = new ArrayList<String>(); for(String x: things) list1.add(x);
My simple question is - what are the <String> ...<String> for? I understand it makes the list1 variable a string, but why is it made like this? do we usualy use <String> when we need to make a variable a String?
My assignment is to create an array list and compare the total salary of two salespeople. I'm wondering if I can use JOptionPane to select an existing sales person from the list and print their information.
I am not having any trouble with the calculations and comparisons, but I am finding limited resources on "searching" for a specific person with JOptionPane.
Here's what I have so far.
public class SalesPeople { String personName; double annualSalary; double salesAmount; double percentComission; public SalesPeople(String xPersonName, double xAnnualSalary, double xSalesAmount, double xPercentComission) {
I have to make an applet that uses an array to list 5 songs and the applet has to scroll the list of song titles, one at a time, each song title should start at the top of the applet and scroll to the middle then, scroll off the right hand side, each new song title should scroll in a different color, the applet should loop, when it gets to the end of the list, start over again at the beginning of the list. the code compiles fine put when I go to run the applet nothing shows up in it and a wall of text appears in the command prompt.
An array which contain a list of names. I let for a user input and I use that to search through the array. For example lets say the string name "Christian" is stored inside the names array and the user types in Chri, the program looks in the array and finds a name that contains Chri and prints them out. How do I go about doing this?
