When I run my code, I get an error with this line
if(Collections.binsearch(dict, word3) != -1) {
I imported the collections utility and everything. Tell me if you need to see more of the code. The exact error is binsearch is undefined for the type Collections.
I have a problem with my code with Junit:
"The method infinityNorm(double[) is undefined for the Type Vektor."
This error pops up for both the euclidian norm and the manhattan norm.
Here is the code:
package de.ostfalia.gdp.ss15;
public class Vektor {
public static void main(String[] args) {
double[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9};
System.out.println("Euclidian Norm: " + euclidianNorm(array));
System.out.println("Manhattan Norm: " + manhattanNorm(array));
euclidianNorm(array);
[code]...
What is the problem here?
Am doing mapreduce in java for hadoop. The below code is for Reducer. i get a problem with the TryParseint. What is this error and how to rectify it?
Error : The method TryParseInt(String) is undefined for the type MaxPubYearReducer
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
[Code] ....
Attached image(s)
Is there a reason why this error is occurring? I can't identify what's causing it to happen.
Java Code:
package tictac1;
import java.util.*;
public class TicTacToe{
//Instance variables
private char[][] board; //2D array of chars for the board
public TicTacToe(){ //creates a board where each space holds whitespace
board = new char[3][3];
for (int row = 0; row < 3; row ++){
[code]...
Let's say we have situation like this:
abstract class A
class B extends A
class C extends B
class D extends C implements SomeInterface
I'm trying to implement a method "doSomething" declared in SomeInterface in class D. While trying to call doSomething in main I get the error message ”The method doSomething is undefined for the type B”
This is my code i main:
B container = new D("1,2,3,4,5,6,7,8");
System.out.println(container.doSomething());
I need container to be an object of type B, because it goes later into a list of type B. According to what I've been told, the only file I need to edit to make this work is class D.
I am trying to run a class with a client code and I get the following error
The method add(TimeSpan) is undefined for the type TEST
Why i get this error?
package timespan;
// Represents a time span of hours and minutes elapsed.
// Class invariant: minutes < 60
public class TimeSpan {
private int hours;
private int minutes;
[Code] ....
I'm writing a code to record Student names and their scores but I don't understand why it says that nextString is undefined. What does that mean? I haven't written much of the code but here is what I have so far
import java.util.Scanner;
public class highScores {
public static void main(String[] args){
Scanner input = new Scanner (System.in);
System.out.print ("Enter number of students: ");
[code]...
I've a simple logic Code to increment a variable from javascript and Send it back to jsp. I just writing simple code to explain the logic. My code will have scritplets. I know usage of scriptlets is inside jsp is oldest but for the sake of logic.
<!--Jsp Page -->
<%
int i=0;
<input type="button" onclick="fun()"/>
%>
<!-- Script as Follows-->
<script>
function fun(){
<%i++;5>
}
</script>
But My value of i is not incrementing its showing that function is undefined
I am new in Collection, as per my knowledge I have already override the hashCode() and Equals() method in Data class, but when I trying to search the element it is giving "not found". find the bug.
import java.util.*;
public class WordCounter {
public static void main(String args[])
{
HashSet<Data> set=new HashSet<Data>();
set.add(new Data("this",2));
[code]....
I am just not sure of some theory in collections, ArrayList and LinkedList maximum capacity depends on the memory allocated to the JVM. But according to few people those list has a maximum capacity of Integer.MAX_VALUE.
According to my experiment, those list has a maximum capacity of Integer.MAX_VALUE since the get method of List accept a parameter of int primitive type (index of element), therefore we can conclude that the maximum capacity of List is equal to Integer.MAX_VALUE.
But what about the Map? get() method of map accepts object(the key of the map). So does it mean that the maximum capacity of Map depends on the memory allocated to our JVM? Or its maximum size is Integer.MAX_VALUE also just like Lists and Arrays? Is there a way to prove it? Is Map designed to hold infinite number of data (disregarding the heap memory space exception)?
And also about Stack, Deque? is it also the same as Map (in terms of maximum capacity)?
Today I installed jdk1.8.0_20 on my computer and typed a simple example code in MyEclipse 6.0 IDE, the code listed below:
import java.util.List;
public class Test5
{
public static void main(String[] args)
{
List<String> features = Arrays.asList("Lambdas", "Default Method", "Stream API", "Date and Time API");
features.forEach(n -> System.out.println(n));
}
}
the MyEclipse Editor shows some errors like "Arrays can not be resolved" and "n can not be resolved".
I did use jdk 8 in the build path, but it seems like the jdk 8 did not function properly.
The Iteratior provides the functionality of traversing and removal which we can achieve through normal for loop and remove() of the data structure.Then, why do we need Iterator explicitly and as an inner class?
View Replies View RelatedI am using this image as a reference to learn the Collection interface better and it seems I must be getting confused with the 'ordered/unordered' types. I thought ordered would mean ordering the objects automatically like a TreeSet using the comparable interface so it could be numerically or alphabetically ordered etc..
Java Code:
public static void main(String[] args) {
Set hashSet = new HashSet();
hashSet.add(1);
hashSet.add(3);
hashSet.add(2);
for (Object o : hashSet){
System.out.print(o + " "); // Prints: 1,2,3 (Unordered but puts the numbers in order....)
[code]...
I have a method that draws a polygon on the screen:
public void poly(List<Point> points) {
//code
}
For the usage of the method, it makes no difference whether points is an array or a List. In fact, switching doesn't even change any of the code in the method since I use a for-each loop. So, my question is, is it a better practice to use a List as an argument, or an array when the method itself doesn't care about which to use?
I have searched on internet but did not find something useful. I do not want to use collections. here's what i have written
class ArrayDemo3
{
static void union(int x[], int y[])
{
System.out.println("Union Elements:");
for(int i=0; i<x.length; i++)
{
for(int j=0; j<y.length; j++)
[code]....
I am confused with the following function signature in the class java.util.Collections.
static <T> boolean replaceAll(List<T> l, T oldValue, T newValue);
I got the other parts but i could not figure out at all what is the meaning of <T> in the beginning.
I am trying to create a java program to sort an array in ascending and descending order. Here is the program I created :
import java.util.Arrays;
import java.util.Collections;
public class ArraySort
{
public static void main(String [] args) {
int [] num = {5,9,1,65,7,8,9};
Arrays.sort(num);
[Code]...
BUT I GET THE FOLLOWING EROOR ON COMPILATION
ArraySort.java:12: error: no suitable method found for reverseOrder(int[])
Arrays.sort(num,Collections.reverseOrder(num));
^
method Collections.<T#1>reverseOrder(Comparator<T#1>) is not applicable
[Code] .....
What's wrong with my program?
I'm doubted regarding the implementation of Collections.binarySearch() method on an ArrayList of objects of a custom class Movie.
Here is the movie class :
public class Movie implements Comparable<Movie> {
String movieName;
String rating;
String director;
String theme;
[Code] .....
The sort/binarySearch in searchByMovieName function is done with natural sorting (and Comparable Interface in Movie class). I mean no comparators involved here. And the comparator that I used for sorting/binarySearching on Movies Director attribute in searchByMovieDirector function is :
public class MovieDirectorComparator implements Comparator<Movie> {
public int compare(Movie movie1, Movie movie2) {
return movie1.getDirector().compareToIgnoreCase(movie2.getDirector());
}
}
But I was not able to implement binarySearch ?? How to implement the binarySearch here. I have google to see only binarySearch working on Arrays or probably ArrayList of String only, but not on ArrayList of custom objects.
My friends and me are trying to make online Test taking system. We got a very basic doubt.
We have developed classes and relationship between classes for example : Online Test Taking system will have admin and student class. And Admin will have list of students.. etc.
But question troubled me was: if we use database to store all data for example student details then I can perform all sorts of operations writing sql query and store result in some other database then what is the need of "ArrayList<Student> field in Admin".??
Question is: We can put everything in database and manipulate using database(sql) functions to manipulate it.Then what is the need of Arraylist of anything which is just used to store object details for example student details....??
Below code I am using to typecast int to char.
char escapeValue = (char)0;
char cha = (char) 10;
escapeValue = (char)(escapeValue * cha); // Here am getting the above error.
I have 38 similar issues in my workspace.
If you have final int i = 1;
short s = 1;
switch(s) {
case i: System.out.println(i);
}
it runs fine. Note that the switch expression is of type short (2 bytes) and the case constant is of type int (4 bytes).My question is: Is the type irrelevant as long as the value is within the boundaries of the type of the switch expression?I have the feeling that this is true since:
byte b = 127;
final int i = 127;
switch(b) {
case i: System.out.println(i);
}
This runs fine again, but if I change the literal assigned to i to 128, which is out of range for type byte, then the compiler complains.Is it true that in the first example the short variable and in the second example the byte variable (the switch expressions) are first implicitly converted to an int and then compared with the case constants?
class Passenger{
String name;
int age;
char gender;
int weight;
public Passenger(){
[Code] ....
This is showing error.....error it gives isthat it cannot change from string type to passenger type......... How to do it??????
Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent
at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
I have a String repersentaion of some Object.I want that object convert back into some class type how can I do this?
View Replies View RelatedI'm trying to parse and compare the content of a zip file. However I'm stuck at what SHOULD be a very simple problem, however I can't seem to find a solution. I have done the following:
ZipInputStream zin1 = new ZipInputStream(fin);
ZipEntry ze1 = null;
fin2 = new FileInputStream(fileName2);
ZipInputStream zin2 = new ZipInputStream(fin2);
ZipEntry ze2 = null;
//fin.close();
ze1 = zin1.getNextEntry();
ze2 = zin2.getNextEntry();
Which gives me the first entry of each zipfile as a ZipEntry type object. I have tried getting the path of the file (inside the zip file) and using this to create a File type object. This does not seem to work though I get:
Exception in thread "main" java.io.FileNotFoundException: My DocumentsmetadatacoreProperties.xml (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
And this is because I get a null return from trying to create the File file1 = new File(correctLocation);
I guess I cannot access the file inside a zip file this way. So my question is how can I make a ZipEntry type object into a File type object?
The objective of the code is to add new records based on existing records with a partial change to the key. I'm getting "type of the expression must be an array type but it resolved to DstidArray" on dsTidRecTbl[i]
String stMajor = request.getParameter("stMajorVersion");
String stMinor = request.getParameter("stMinorVersion");
String stPatch = request.getParameter("stPatchVersion");
StringBuffer stKeySB = new StringBuffer(stMajor+stMinor+stPatch);
String stKey = new String(stKeySB.toString());
DstidArray dsTidRecTbl = new DstidArray(stKey);
request.setAttribute("dsTidRecTbl", dsTidRecTbl);
[code]....