I'm having difficulty implementing keyboard and mouse event handlers at the same time for a program designed to notify the user when a key has been pressed or a mouse button clicked.
I can make and understand a program that does one or the other, but when I try to combine them, either the keyboard only or the mouse only works.
1. public void f(int i, long j){System.out.println("1");} 2. public void f(int...i){System.out.println("2");} 3. public void f(long l, long p){System.out.println("3");} 4. public void f(int j, int k){System.out.println("4");}
With the function call: f(1,2), the output is: 4.
My questions are the following:
a. Why is the compiler choosing #4 to execute and not the rest? b. If I remove 4 and replace it with: 5. public void f(long j, int k){System.out.println("5");}, why does the compiler now give an error complaining of ambiguous function defintions when 'f' is called?
I've tried implementing the compareTo method in several ways and no luck.. I keep getting errors and now it just says bad operand type for binary operator with the ">" symbol and also the less than. I'm attempting to give an implementation for the compareTo method so it compares the value of the requestDate instance variable of the two objects. if the calling object of request is greater then I have to return ""1" if it's smaller then returns "-1" and if they are the same then returns value of "0"
package librarysystem_phase2; import java.io.Serializable; /** * This class represents a request a member makes to checkout or download an item from the library. */ public class Request implements Serializable, Comparable<Request>
I'm new to Methods and do not really know how to write a method header. What would an appropriate header look like for the following instance? getFilename: This method takes no parameters. It asks the user for a filename. If that file exists, it returns the filename. If it does not exist, it asks the user for another filename. It continues to ask for filenames until the user gives the name of a file that exists.
Also, how would I make a return tag for this and call it into the main method.
I'm new to Methods and do not really know how to write a method header. What would an appropriate header look like for the following instance? getFilename: This method takes no parameters. It asks the user for a filename. If that file exists, it returns the filename. If it does not exist, it asks the user for another filename. It continues to ask for filenames until the user gives the name of a file that exists.
Also, how would I make a return tag for this and call it into the main method.
The class Overloading below asks for two names and prints three different greetings. Your task is to write the class methods missing from the class declaration. Methods print the greetings as shown in the example print.
Hint:The names and parameter types of the needed methods can be checked from the main method because all methods are called there. This exercise also does not require you to copy the source code below to the return field.
The method declarations will suffice.
Example output Type in the first name: John Type in the second name: Doe
********** Hi! ********** Hi, John ********** Hi, John and Doe **********
import java.util.Scanner; public class Overloading { public static void main(String[] args) { String firstName, secondName;
Can I assign multiple values to one variable? For example I want myNum = 0 thru 9 you see im trying to program a password checker program to verify that the password meets all the criteria 8 char long, 1 upper case, 1 lower case, 1 numeric, 1 special, and don't contain and or end
My application depends on eight default user roles (or account types). They can be renamed or disabled, but should not be deleted. I want to protect them from deletion using their uuid value from the db. How can I pass their uuids into a single variable so I can use that single variable in my conditional statement? If I should use an array, any example of how I might do this?
Can I store multiple rows of a table in a two dimensional string array in java.. The table has 3 columns and approximately 10,000 rows.. Some pointers for coding to achieve this...
After this problem is fixed, my math game will run. The answer variable is supposed to be equal to the cases in the second switch statement by random but I get errors whenever I try to initialize it this way. I have been writing this program for almost 5 days now and it is finally wrapping up. Why I can't map the answer variable to the second switch statement the way I want to?
package pkgnew; import java.util.Scanner; import java.util.Random; public class New { public static void main(String args[]) { //Declare and construct variables Random randomnum = new Random(); int fnum, snum, answer;
I'm trying to build a program that will output what will ultimately look like a simple mario level turned on its side. As part of my output I need the user to define what mario looks like. I do this using Scanner and save the input to String mario. When I try to use that variable in another method it gives me troubles.
import java.util.Scanner; public class Mario2 { public static void mario() { //user defines mario String mario = ">->O"; Scanner keys = new Scanner(System.in); System.out.println("What does mario look like?"); mario = keys.next(); System.out.println("Mario now looks like: " + mario);
My code has a method where the users input a bunch of variables and then those variables get added together in a new variable. What I want to know is how do I call the variable that is in the other method to another method?
import java.util.*; public class Calc{ public static void main (String [] args){ determinevalue1(); determinevalue2(); determineTotalvalue(double value1, double value2);
I am having an issue with a small part of my project. i am supposed to make a hash table with a file containing words. The file is being passed into my constructor, where i basically just all it "filename" of type string. Im supposed to get the contents of the file and put it into the table. the problem I'm having is making the connection between my constructor and a method called "start" which basically does all the work. Im not sure how to go by doing this, how could i use the variable "filename" from my constructer in my start method?:
import java.io.*; import java.util.*; public class WordCount { //private fields, including your HashMap variable HashMap<String,Object> hmap =new HashMap<String,Object>();//(table size,load factor) public WordCount( String infileName){ String filename =infileName;
If I have a method that creates a new variable (the name of which is a string argument for the method). Can I get that variable to appear in the workspace in the variables pane?
So instead of just using return to output the variable how do I get in that variables pane?
Now that I have figured out how to return a single variable from a method I am on to the next step, I need to return 2 or 3 variables from a method. I have searched the internet on how to do this to no avail (am I doing the wrong search? I do not know) but what I need to do is return a second (and eventually a third variable)
Here is what I have
private static String Engine() { String engine = ""; int enginePrice = 0; System.out.println("Choose a engine size:"); System.out.println("[4] cylinder");
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?
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.
Say I have two classes, Author and Book, and I have 2 author objects and 10 book objects. I would like to know how to do two things:
1) Make some sort of connection that makes clear that author X wrote books A, B and F. 2) Call a method from a book object that is connected to an author.
Seeing as I don't know which books will be connected to an author, is there some way to call a method of an object bases on a variable object name? Something like call the getFirstPage() method for every book that is linked to author X?
I have a multithreaded application. I have a Logger class with static methods that I use across threads. Would it behoove me to add the synchronized keyword to the static methods of the Logger class since I use this class statically in different threads?
this code won't compile because selected row must be declared as final because of it being defined outside the window listener. Is their anyway around this? If I make it final the first time that the variable is called it keeps it starting value until the GUI is closed.
butEdit.addActionListener (new ActionListener () { @Override public void actionPerformed (java.awt.event.ActionEvent evt) { int selectedRow = table.getSelectedRow (); final String [] values = custTableModel.getRowValues (selectedRow);
