So, I am learning Swing, and Swing Layouts. I just came across a really confusing (for me) line of code.
Java Code:
setLayout(new BorderLayout()); mh_sh_highlight_all('java');
So, this is weird for me because I don't really understand why the BorderLayout class constructor is being initialized as a parameter for the setLayout..
I was practicing my java skills and came across an exercise in which a non parameter constructor calls a two parameter constructor. I tried a few searches online but they all came back unsuccessful. This is the part I am working on:
public PairOfDice(int val1, int val2) {
// Constructor. Creates a pair of dice that
// are initially showing the values val1 and val2.
die1 = val1; // Assign specified values
die2 = val2; // to the instance variables.
}
public PairOfDice() {
// Constructor that calls two parameter constructor
}
I tried calling the two constructor using the line "this(val1, val2)" but I get an error because val1 and val2 are local variables.
Then I tried to use the same signature: "this(int val1, int val2)" but that didn't work either.
I have a class of Date with a constructor with 3 parameters in it. Those 3 parameters are int data type just to enter month, year, day.
I have another class called Author which has a constructor of Date diedDate; as a parameter passing to the Author constructor.
I was asked to call the Date parameter is null, call the default constructor but I thought for the Date parameter I could only enter something like 0,0,0 instead of typing in null, null, null because null is for String data type isn't it?
I need to pass user input from the main method, which is then validated using another method that is returned as a valid score, and then I pass the valid input to another method that stores the data in an array. The array is initialized within the method. I tried to use an if-else statement to initialize the array, because I originally did this at the beginning of the method. I soon learned that I was creating a new array everything I accessed the method. Needless to say, this isn't working either.
public static void main(String[] args) {
int judges = 7;
float[] validScores = new float[judges];
for (int i = 0; i < judges; i++) {
float score = -1;
[Code] ....
Instructions
Create a WordCounter class with a constructor that takes a file name as a parameter
The class should have two fields: one for the file name and one for a HashMap to store word count information
The constructor should call a private method, countWords, that reads in the file and counts the word frequencies
The class should contain a get method for each field, as well as a print method that prints out the map in the following format:word:frequency
When printing, the map should be sorted by either the word order or frequency (Hint: see Collections.sort)
You should include the sample text file on Blackboard. This is what i got so far
Java Code:
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Scanner;
public class WordCounter
[Code] ....
I was following a tutorial for libGdx and suddenly became confused by the following syntax:
up.addListener(new ClickListener(){
public void clicked(InputEvent event, float x, float y){
position.y += 1f;
//currentFrame = animation.getKeyFrame(12);
}
});
"up" is basically a text Button:
TextButton up = new TextButton("up", textButtonStyle);
and .addListener is just one of the methods "TextButton" has (actually I think its inherited from "Button" but that doesn't matter).
Basically my question is what's going on inside the parentheses? From what I see its a new instance of "ClickListener" but then suddenly they override an actual method within. Is this simply just a way to override a method from the ClickListener class or is it something else?
Java SE Runtime Environment build 1.8.0..This is part of the code:
public static int addAddress (String[] number, boolean[] front, double[] total) {
int num = 0;
double ffee = 0;
/*boolean value = false;*/
[code]...
I have tried using the line of code commented out, /*boolean value = false;*/. However, another error is displayed. The compiler shows the following...
Inspection.java:33: error: incompatible types: boolean cannot be converted to boolean[]
front[num]= defineFront(num, value);
^
Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output error...I know that boolean values are by default stored as false, once you create the array. However, I'm having trouble passing the variable to the method.
I have a method that accepts as a parameter an object:
public void addClient(Client c){ }
Client is a class which has a constructor that has two String parameters:
public Cliente (String name, String lastname){
this.name = name;
this.lastname = lastname;
}
In the main add a Client in this way:
addClient(new Cliente("first", "second"));
Now, i have an array of Client, so I would like to enter within this. Example:
public void addClient(Client c){
for (int i = 0; i<client.length ; i++) { // client is an array of Client object
client[i] = c; // Enter a c in the array, but does not work!
System.out.println("test "+clienti[i]); // print Client@15db9743
}
}
I have used the println for check if worked insertion, but the result shows no
how is cast a class at a methods parameters? i have a problems in a methods paramter. i draw red line my exception and mymethods is orage color ....
Caffe drink = new Caffe();
CoffeCup cup = new CoffeCup();
cup.setTempeture(100);
drink.drinkcaffe((CaffeCup)(cup.getTempeture()));
[code]....
I was going through some lectures online and found that to compare or even swap, the use of comparable or comparator argument like
public static boolean less(Comparable v,Comparable w)
{
return v.compareTo(w)<0;
}
public static void swap(Comparable []a,int i,int j)
{
Comparable swap=a[i];
a[i]=a[j];
a[j]=swap;
}
I did not get the use of passing Comparable or Comparator to the function as parameters. Object as parameter could have been used too?
I have the following method:
public static void doSomething(List<? extends GenericClass> input)
{
// op
}
^
This compiles and works, ensuring I can only pass in a List of a type extending GenericClass.But now I want it to accept an Array instead of List. This is where I'm stuck:
public static void doSomething(<? extends GenericClass>[] input)
{
// op
}
^
A wrong guess at the syntax which does not compile. One solution is to convert Array into ArrayList before calling the 1st method above, but I'd rather bypass this if possible.
I have a drop-down which contains the four sections simple buttons(filters). When click any of these buttons some settings are applied. I have successfully auotmated it using simple if else and switch but in that case i have to use 8 parameters(8 are the number of button)
public void editFilters(WebElement filter1, WebElement filter2, WebElement filter3, WebElement filter4,WebElement filter5,WebElement filter6,WebElement filter7,WebElement filter8 String edit, String expectedColour) {
switch (edit) {
case "selectFilter":
if (filter1 != null) {
[Code] .....
But want to make it more effective by using hashes. I do not want to use 8 different parameters to perform action on the respective button.
So now what i want to implement.
Create a method in which i pass the parameter1 as hash and 2nd parameter as 0 or 1, 0 means unSelectFilter and 1 means select the filter.
With parameter 1, in code i want to pass the name or xpath or anything else for any number of filters , that those filters names should be stored into that hash and then by passing 0 or 1, i can select/unselect those filters.
I am following this article [URL] .... till now I have made some code
This is my Interface
public interface Comparable<T> {
public int compareTo(T o);
}
And this is my class where I am using Bound Type Parameter on Generic Methods
public class GenericMethodBoundType {
public static <T extends Comparable<T>> int countGreaterThan(T[] anArray, T elem) {
int count = 0;
for (T e : anArray)
[Code] .....
What else I need to do both in main method and at what parameterized types I need to pass at the class?
how to get an access to the method with a parameter of class type variable, lets say: public void insert(Record newRecord, int pos)?
View Replies View RelatedThe instructions:
Write a method named hopscotch that accepts an integer parameter for a number of "hops" and prints a hopscotch board of that many hops. A "hop" is defined as the split into two numbers and then back together again into one.For example, hopscotch(3); should print:
1
2 3
4
5 6
7
8 9
10
how to start this program.
If you write
byte b = 100; it works (implicit conversion of implicit int literal 100 to byte.
But if you have a methodvoid bla(byte b){}
And want to invoke it with a literal (which is an int by default):bla(8) then there is no implicit conversion.
Is the byte b = 100; just an exception in Java? And is it the rule that one has to explicitely cast (narrow) integer literals when passing to smaller-than-int types?
so i have this question where it wants me to create a recursion method that takes ONLY THE ARRAY as a parameter, and without using loops or static variables inside the method, and then the method returns the smallest value in that array. However, i tried making the simple if statements where i compare the first element of the array with the second element using the length of the array and decreasing it to get the next elements and compare it again by calling the recursion method, but the problem is when i call the method again, the length does not decrease, even if i store it in a variable, the variable will initialize itself again, and the length wont change.
View Replies View RelatedIn my book for learning java, one of the questions asks us to create a method header named convertTOKM that takes an int parameter, which is the number of miles, and returns a double value for the converted value in kilometers. I made one, but wanted to know if I was right in any way.
Here it is:public double convertTOKM(int miles, double kilometers){
I'm doing an assignment where a method receives a Queue as a parameter then convert it into a stack, I made it but now I want to try it in my main, but how can I do this? there's no toString and I cant use a for loop because I'm using a queue and not an array. This is the head of my method:
public static void QueueStack(Queue<Integer> q){
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;
[Code] .....
Passing Information to a Method or a Constructor
They show a line of code that goes like this:
public Polygon polygonFrom(Point[] corners) {
// method body goes here
}
So from what I understand this is a constructor method for a Polygon object from the Polygon class. What I dont get is the name of the method polygonFrom()
Shouldn't a constructor for a Polygon just have the same name as the class? Because from earlier examples in the tutorial it seems to me that this is what has been done
For example:
public Bicycle(int startCadence, int startSpeed, int startGear) {
gear = startGear;
cadence = startCadence;
speed = startSpeed;
}
Why in this code testSon class void display() method is called instead of testFather class void display()
class testFather
{
void display() {
System.out.println("This is testFather class");
}
testFather() //testFather constructor {
display();
[Code] .....
Output : This is testSon class /* why not This is testFather class*/
This is cons of testSon class
I am practicing some basic recursion and I was trying to solve this problem
Write a method sumTo that accepts an integer parameter n and returns the sum of the first n reciprocals. In other words:
sumTo(n) returns: 1 + 1/2 + 1/3 + 1/4 + ... + 1/n
For example, the call of sumTo(2) should return 1.5. The method should return 0.0 if passed the value 0 and should throw an IllegalArgumentException if passed a value less than 0.
This is my attempt to do it , however my output is always a 0.0 , and i do not understand why :
public static double sumTo(int n ){
if(n<0){
throw new IllegalArgumentException();
}
else if (n==0){
return 0.0;
[Code] .....
i have to "Write a method called addToOverThirty which takes the array nums3 as a parameter. It adds 1 to all numbers that have a value greater than 30 in the array.
Add a call to the addToOverThirty method, then display a message telling what the output is followed by the results For example:The nums3 array after adding 1 to all numbers greater than 30 is10 6 15 and so on (check with the values you assigned to nums3)"its pointless because we were told not to make the array have a number over 30.
import java.lang.*;
import java.util.*;
public class LastProject
public static void main(String[] args) {
int nums1[] = new int[15];
int nums2[] = new int[15];
int nums3[] = {5,2,15,8,26,22,1,29,4,23,30,11,19,6,24};
[code]....
I have two methods with parameters out of the main method, both of them work fine alone but I am finding a problem to use them together. I need to use the parameter of Method one in the second Method.
View Replies View RelatedI don't understand, why when in the constructor of the superclass A the method init() is called (line 4), the overridden version of the subclass is invoked (line 26) and not the superclass version (line 7):
class A {
public A () {
init();
}
public void init() {
System.out.println("test");
[Code] ....
I would have guessed that above code prints
test
1
But instead you get a NPE (because when the constructor of B is invoked
public static void main(String[] args) {
new B();
}
Then there is first the implicit call to super:
public B() {
s = " ";
init();
}
Which is the constructor of A:
public A () {
init();
}
But here now this init() method is not the version of A ( public void init() {
System.out.println("test");
}) but the overriden version of the subclass (B): public void init() {
System.out.println(s+=s.length());
}...
Which throws an NPE of course, because the initialization of s has not occured yet (it happens only after the implicit call to super() has finished (see public B() {
s = " ";
init();
}))