Compile Error - Empty String?
Jul 1, 2014
I'm writing basically my first program for school. I've written small ones, following instructions, but this is the most vague. I'm having issues. I can't figure out what the error means. I'm not done with the code, but I think the ArrayList is throwing me off. I'm trying to gather user input and sum the total. Here's the code:
package graduationplanner;
import java.util.ArrayList;
import java.util.Scanner;
import java.lang.Double;
public class GraduationPlanner {
public static void main(String[] args) {
[Code] ....
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Apr 16, 2015
I am having issues with the program below everything works but I can't figure out a way to add code that if a user just hits enter without inputting anything it says "entering in nothing is not a valid choice" I am stuck on how to compare a int to a string ...
//import statements
import java.util.*; //for scanner class
// class beginning
public class Guess {
public static void main(String[] args ) {
//Declare variables area
[Code] ....
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Apr 16, 2015
I made a guess a number program but I am having issue figuring out a way that when a user enter's in nothing for the program to spit out a message saying "hey entering nothing doesn't work try again" then ask for input. I have done some research and from what I have found is to read the input in as a String rather than int, and use something like Integer.valueOf() to get the integer value but I am completely lost on how to apply that to my program here is my code
//import statements
import java.util.*; //for scanner class
// class beginning
public class Guess {
public static void main(String[] args ) {
//Declare variables area
int guess, secretNumber = (int) (Math.random() * 10 + 1), lowGuess,highGuess;
[Code] ....
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Feb 9, 2015
I am a C# developer but need to do some java development. The code produces the following error.
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
...
HashMap<String, String > myMap = new HashMap<String, String>(){{
put("a","b");
}};
myMap.put("foo", "bar");
myMap.put("Sna", "foo");
...
Generates this error
C:/FSC/apache-tomcat-6.0.41/webapps/aspen/temp/x2_8656248460570782763/x2_5214718769032742331/StudentExport.java:47: error: <identifier> expected
myMap.put("foo", "bar");
^
What am I missing?
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Oct 13, 2014
I've been beavering away with Java for a few months. But as with all languages the String implementation looks designed to trip up even experienced programmers.
My current development gets data from various sources outside my control. When I get a string I want to test if it is empty/null/or whatever. Simple enough one thinks.
But if you search the internet you see everone seems to have a slightly different approach. So what is the best way of determining that a string is not useful to you?
I've had success with this
if(string == null || string.length() == 0)
But I've seen people using methods - not necessarily of String (e.g equals, empty) and regular expressions.
What is the best approach to this considering coding efficiency and/or processing efficiency (accepting you'd have to be processing a lot of strings for the latter to be an issue).
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Jul 23, 2014
programming altogether and after almost reaching half way in the 'Head first java' book I decided to try and apply some of what I've learnt so far and write my first 'Object orientated' program. As this is pretty much the first program I've ever written, I decided to write a program to ask for two integers and add them both together and then present them to the user (the goal eventually being a basic fully working command line calculator with +,-,* and /. I'm expecting many compile errors but not the following errors below.
I have three .java files contained within a folder and after trying to figure out how to compile all three files (as they use one another) all at once, I came across this ---> javac *.java
so I typed this in the command line whilst in the directory containing the three files assuming *.java is the best approach and then I receive the following errors:
inputOutput.java:10: error: cannot find symb
c.addition() = intIn.nextInteger();
^
symbol: variable c
location: class inputOutput
[Code].....
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Sep 24, 2014
import java.util.*;
import java.lang.*;
class Bank {
String name;
float acc_no,balance;
void accept(String str, float no, float bal)
[code]....
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Feb 3, 2015
I keep getting the error Admit.java:10 cannot find symbol
import java.util.*;
public class Admit {
public static void main(String[] args) {
sayIntro();
Scanner console = new Scanner(System.in);
System.out.println("Information for applicant #1:");
getScore(console);
getGPA(console);
[Code] ....
The compiler then reads:
Admit.java:10: error: cannot find symbol
score1(ACTScore, SATScore, GPAScore);
^
symbol: variable ACTScore
location: class Admit
Admit.java:10: error: cannot find symbol
[Code] .....
10 errors
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Dec 23, 2014
i wrote this program:
class hellojava
{
public static void main(string[] args)
{
system.out.println("hello java");
}
}
Then i saved this file with name hellojava.java(notepad) in C drive in separate folder c:myjavaapp(not in c:java folder).
When I am compiling(with javac hellojava.java) it shows following error:
cannot find symbol public static void main(string[] args), and also says package system doesnot exists system.out.println("hello java");
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May 29, 2014
I have a msg object that contains an ArrayList<Integer> collection. However, in order to send the elements in the array over the udp socket, it needs to be sent as a byte[] array. So why am I using ArrayList<Integer> over byte array in first place? Well when I receive data from socket from embedded c program, I need to get an unsigned representation of the data, and thus I need to store it in integers, since bytes in Java are unsigned and unsigned chars in c that are greater than 127 will yield incorrect values in java. But when I send an ack back over the socket, I need to send the data back as bytes. So I convert the ArrayList<Integer> to a byte array:
Java Code: byte[] data = msg.toByteArray();
DatagramPacket response = new DatagramPacket(data, data.length,
packet.getAddress(), packet.getPort());
public class Gprs {
...
public byte[] toByteArray(){
[Code] ....
The problem is I get an "Cannot cast from Integer to byte" when trying to cast the integer to byte: data[i] = (byte)m_data.get(i);
How can I resolve this?
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Feb 24, 2014
I found an error in these code when I compile it
"uses or overrides a deprecated api"
Java Code :
import oauth.signpost.OAuthConsumer;
import oauth.signpost.commonshttp.CommonsHttpOAuthConsumer;
import org.apache.commons.io.IOUtils;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
public class JavaRestTweet {
[Code] .....
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Mar 8, 2014
This is the exception message I am getting when I run the program and I select a job from the check box and enter an hour amount.
import javax.swing.*;
import java.awt.*;
public class HourPanel extends JPanel {
private double hours;
String textField;
[Code] .....
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Jul 26, 2014
I have the code below that just keeps getting the user's name and displaying it until the user enter's an empty string. Well, to simulate that, I just hit the keyboard instead of entering any name but for some reasons I am not seeing in my code, the programme just keeps looping.
System.out.println("Enter your name :
");
Scanner st = new Scanner(System.in);
while(st.hasNext()){
System.out.println("Enter your name :
");
String name = st.nextLine();
System.out.println(name);
if(name==" ") break;
}
System.out.println("you are out of the while loop now!!");
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Feb 6, 2014
I'm trying to get the jsessionid cookie value using the following line in my jsp. It always returns empty string. Is this correct behaviour?
response.encodeURL("")
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Jul 21, 2014
This is likely a simple matter, but my error is confusing given the line it flags matches a working project I have. I get the following error on line 6 in the Controller:
cannot find symbol
v.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
...........................................^
(carrot at the J)
My view file:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class View extends JFrame{
private JLabel lbl;
private JButton btn;
[Code] ....
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Feb 14, 2014
This method accepts 1 integer, amount (the amount of money). Output the minimum number of in quarters, dimes, nickels and pennies used to make up the amount. For example, an amount of 32 would require 1 quarter, 1 nickel and 2 pennies.
This is the question^
My codes are:
public static int change (int amount) {
int quarters = amount / 25 ;
int firstresult = amount % 25 ;
return quarters ;
int nickel = firstresult / 5 ;
[Code] .....
The codes were working when i used System.out.println instead of return, but our teacher required us to use return (functions).
I get the compile error: Unreachable statement.
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Jul 5, 2014
I have an empty string and I want to add to it crosses and naughts. I want to simulate a board of TicTacToe game. My goal is print out 5 strings like this : "xox xxx oxo". There are 3 groups of symbols separated with a space. The crosses and naughts are filled randomly.
Random rand = new Random();
char[] characters = new char[] { 'x', 'o' };
int numOfTimes = 0;
while (numOfTimes < 5)
{
String board = "";
String space = " ";
for (int group = 0; group < 3 ; group++)
[Code] .....
Why my code doesn't output the desired result ?
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May 23, 2015
Netbeans do not detect any syntax errors, but I when I check the build it retuned areas they were a few; It's a simple program name 5 people, gade them then do final calulatoins it's called "grade tool.
heres the code
package gradingapplication;
import java.util.Scanner;
public class GradingApplication {
public static double score(double score){
if(score >= 90){
System.out.println("A");
[code]...
~Problems~
1. It has no gui, I don't know java fx, is java groove used? awt is useful for creating spam bots in robot class, I know it's not very useful but it's so much fun.
2. the sections where I use the scanner.
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Jul 29, 2013
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...
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Apr 7, 2015
The project is a program that allows the user to enter students and enter grades for each student. One of the requirements is that if there is already a grade stored for the student that it will display the previous grade. IF the user then enters a new grade the new grade will be stored. IF the user simply presses enter (enters an empty string) nothing is done. I have everything working except for the requirement of doing nothing if the user enters an empty string. If I just press enter at this point I get a NumberFormatException.
The below code is a method "setTestGrades" from the student class. This method iterates through each student object stored in an array list and then checks if there is a previous grade (Requirement# unset grades have to default to -1) before allowing the user to set a new grade.
public void setTestGrades(int testNumber) { //Sets the grade for the specified test number for each student in the arraylist.
testNumber -= 1;
Scanner input = new Scanner(System.in);
for (int i = 0; i < studentList.size(); i++) {
System.out.println("Please enter the grade for Test #" + (testNumber + 1) + " For Student " + studentList.get(i).getStudentName());
[code]....
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Jul 10, 2014
I have a code in which I am reading input from System.in and Destination is some where else
Here is my code
File file=new File("D:/output.txt");
OutputStream os=new java.io.FileOutputStream(file);
Scanner scanner=new Scanner(System.in);
System.out.println("Enter Data to write on File");
String text=scanner.nextLine();
int c=Integer.parseInt(text);
int a;
while((a=c.read())!=-1)
os.write(a);
System.out.println("File Written is Successful");
In the line while((a=c.read())!=-1)
a compile time error is shown "cannot invoke read on primitive data type int"
Where I am going wrong?
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Apr 15, 2015
I decided to code this quiz I took in class about asking the user to input a string and the code is suppose to check for upper case letters. If a upper case letter is found, it should increase a count by one. Once the check is done, it should display the number of uppercase letters. For some reason I am getting this weird compile error stating that symbols can't be found...
Java Code:
import java.util.*;
import java.lang.*;
public class StringCheck{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("please enter a string: " );
String s = input.nextLine();
[Code] ......
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Jan 25, 2015
public class op{
String word = "Hello"; //my variable
public void reverseword() //My function {
for(int i =word.length();i>=0 ;i--) {
System.out.println(word.charAt(i));
[code]....
when i call function in main i have this error:
run:
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 5
at java.lang.String.charAt(String.java:658)
at javacourse.Car.opname(Car.java:35)
at javacourse.JavaCourse.main(JavaCourse.java:24)
Java Result: 1
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Jan 29, 2014
Below is my first ever code. I bolded where i am getting a syntax error. Why am i getting an error here if i assigned that word to a string?
public class BeerBottleTest {
public static void main(String[] args) {
int beerNum = 99;
String bottle = "bottles";
while (beerNum > 0) {
if (beerNum == 1) {
bottle = "bottle"; }
[Code] ....
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Jul 21, 2014
I am currently trying to split the string "EAM est" between the part. I have gotten the code to work if the was a -. But I can't see why the error is occuring
I have tried
String test = "EAM-testing";
String[] parts = test.split("-");
System.out.println("parts[0] = " + parts[0]);
System.out.println("parts[1] = " + parts[1]);
String test1 = "EAM esting";
String[] parts1= test1.split("");
[Code] .....
The error occurs at line: String[] parts1= test1.split("");
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Sep 28, 2014
I have this error that keeps coming up any time I select one of my buttons. It actually doesn't hinder the performance of the project, everything works. But I am concerned I missed something and errors are never a good sign.On a slightly different note, I would like to figure out what the best way to format my output would be? I would like it to display as "100.00 F". I have a couple ideas on how to get the F symbol (or other symbol) by inserting something like
String degreesymbol = "F" or whichever it is and then returning that in the output string later. I can't get the decimal formatted correctly and I don't know how to print the degree symbol.Here is the code
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
[code]....
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