Hi you can call me Kenshi. I am a highschool student trying to take a online programming class. I would ask my teacher but she almost wrecked my laptop beyond repair because she knows nothing about this. here is my problem.... A few weeks ago i typed up a program finding the surfacearea of a cube. And ever since then when ever i try and run a program it runs the cube program instead. I deleted the project and when i did i got the Java.lan.NoClassDefFoundError. I have heard that i have to delete the Cashe of the program, i had to wipe my computer (due to my teacher) and that didnt work. I followed the program instructions on the Fundamentals of Java Textbook. And when i re typed the program once i got my laptop back and running I still go the error. If you can help it would make This one Very Happy. Below i will provide the whole error code.
java.lang.NoClassDefFoundError: studentapps/StudentApps (wrong name: StudentApps/StudentApps)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:791)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:476)
Exception in thread "main" Java Result: 1
BUILD SUCCESSFUL (total time: 1 second)
Again Much appreciated!!
EDIT: This is the code of the Class its self.
package StudentApps;
import java.util.Scanner;
public class StudentApps {
public static void main(String[] args) {
Student student1 = new Student();
Student student2 = new Student();
Scanner reader = new Scanner (System.in);
String name;
int score;
System.out.print("Enter the first students Name: ");
name = reader.nextLine();
student1.setName(name);
for (int i = 1; i <= 3; i++){
System.out.print("Enter the student's Score");
score = reader.nextInt();
student1.setScore(i, score);
}
reader.nextLine();
System.out.print("Enter the second students name: ");
name = reader.nextLine();
student2.setName(name);
for (int i = 1; i <= 3; i++){
System.out.print("Enter the student's Score");
score = reader.nextInt();
student2.setScore(i, score);
}
System.out.println(student1);
System.out.println(student2);
if (student1.getHighScore() > student2.getHighScore()){
name = student1.getName();
score = student1.getHighScore();
}else{
name = student2.getName();
score = student2.getHighScore();
}
System.out.println(name + " has the highest score: " + score);
if (student1.getAverage() > student2.getAverage()){
name = student1.getName();
score = student1.getHighScore();
}else{
name = student2.getName();
score = student2.getAverage();
}
System.out.println(name + " has the highest average score: " + score);
}
}
Hard to tell without actually seeing your code. But notice the first line:
studentapps/StudentApps (wrong name: StudentApps/StudentApps
There is studentapps and also StudentApps in first parts before the slash '/'. Don't you have somewhere this typo?
Related
Hello I am new to apex and soql, I would like some help on my test class, below is the code i am having trouble with,
public class UpdateMyCard {
#AuraEnabled(cacheable=false)
public static Card__c updateCard(Double Amount){
String userId = UserInfo.getUserId();
Card__c myCard = [SELECT Id, Card_no__c, total_spend__c From Card__c Where OwnerId =:userId];
myCard.total_spend__c = myCard.total_spend__c + Amount;
try{
update myCard;
}catch (Exception e) {
System.debug('unable to update the record due to'+e.getMessage());
}
return myCard;
}
}
Test Class
#isTest
public static void updatecard(){
UpdateMyCard.updateCard(200);
}
Error:
System.QueryException: List has no rows for assignment to SObject
Your code assumes there's already a Card record for this user. And it's exactly 1 record (if you have 2 your query will fail). I'm not sure what's your business requirement. Is it guaranteed there will always be such record? Should the code try to create one on the fly if none found? You might have to make that "updateCard" bit more error-resistant. Is the total spend field marked as required? Because "null + 5 = exception"
But anyway - to fix your problem you need something like that in the test.
#isTest
public static void updatecard(){
Card__c = new Card__c(total_spend__c = 100);
insert c;
UpdateMyCard.updateCard(200);
c = [SELECT total_spend__c FROM Card__c WHERE Id = :c.Id];
System.assertEquals(300, c.total_spend__c);
}
I am having trouble getting "hours" int value from hive box and get the sum of all hours total and display it in a card as a String hours. what I have is:
var data = fastBox.values.where((element) => element.hours !=
0).toList();
if (fastBox.isNotEmpty){
int hoursInt = data.reduce((value, element) => {
value.hours + element.hours
});
hours = "${hoursInt.toString()}";
} else{
hours = "0 " + Languages.of(context)!.hours;
}`
i am getting error:
Class 'List<dynamic>' has no instance getter 'hours'.
Receiver: Instance(length:1) of '_GrowableList'
Tried calling: hours
my hive is:
#HiveType(typeId: 4)
class FastHive{
#HiveField(0)
final int days;
#HiveField(1)
final List<DateTime> dates;
#HiveField(2)
final int hours;
#HiveField(3)
DateTime startTime;
#HiveField(4)
DateTime endTime;
FastHive(this.days, this.dates, this.hours, this.startTime,
this.endTime);
}
just learning here. pls, help! Thank you!
I wanted to know if there is a way to check and validate a field when using the CsvRoutines package. Basically I want to process a row if the first column has only numbers and skip/possibly throw an exception otherwise. I'm guessing #Validate annotation released in 2.7.0 can be used to achieve this. But I would like to know if there is any other way to achieve the same with earlier versions like 2.5.9?
Author of the library here. There's no other way other than updating to the latest version. Is there any reason in particular why you can't upgrade?
Update: you can put the #Parsed annotations on the class' getters or setters and perform the validations in them. That is probably the cleanest way to go about it. For example:
class Test {
private Integer number;
//accepts a String here... so this is straight from the parser before it tries to convert anything into an integer - which lets you validate or throw a custom exception
#Parsed
void setNumber(String number){
try{
this.number = Integer.valueOf(number);
} catch(NumberFormatException e){
throw new IllegalArgumentException(number + " is not a valid integer");
}
}
}
Another alternative is to use a custom conversion class. Copy the code of class ValidatedConversion, used in the newest version, then create subclass like:
public static class RangeLimiter extends ValidatedConversion {
int min;
int max;
public RangeLimiter(String[] args) {
super(false, false); //not null, not blank
min = Integer.parseInt(args[0]);
max = Integer.parseInt(args[1]);
}
protected void validate(Object value) {
super.validate(value); //runs the existing validations for not null and not blank
int v = ((Number) value).intValue();
if (v < min || v > max) {
throw new DataValidationException("out of range: " + min + " >= " + value + " <=" + max);
}
}
}
Now on your code, use this:
#Parsed(field = "number")
#Convert(conversionClass = RangeLimiter.class, args = {"1", "10"}) //min = 1, max = 10
public int number;
I didn't test this against an old version. I think you may need to set flag applyDefaultConversion=false in the #Parsed annotation, and make your conversion class convert a String into an int in addition to run the validations.
All in all, that's quite a bit of work that can easily be avoided just by upgrading to the latest version.
The following is my constructor for a Student object. I will be using a list of student. I need to store the list so even if the program is turned off, I can still access all the contents. The only way I could think of was to use reader/writer and a text file.
1) Is there a more efficient way to store this information?
2) If not, how can I use reader/writer to store each field?
public Student(String firstName, String lastName, String gender, String
state, String school, String lit, String wakeUp, String sleep, String
social,String contactInfo, String country, String major) {
this.firstName = firstName;
this.lastName = lastName;
this.gender = gender;
this.state = state;
this.school = school;
this.lit = lit;
this.wakeUp = wakeUp;
this.sleep = sleep;
this.social = social;
this.contactInfo = contactInfo;
this.country = country;
this.major = major;
}
The possibilities are really project specific and subjective.
Some possibilities include:
CSV file which makes it easy for exporting to other programs and parsing data
Online server which allows access from any computer that has the
program and an internet connection
Text file which works for local devices that won't require many
additions
It really just depends on how you want to implement it and what method suits your needs best.
To use reader/writer to store your fields, you could use the accessor methods of each variable to store them line by line in your text file. Below is some sample code to get you started on writing to the file:
PrintWriter outputStream = null;
try {
outputStream = new PrintWriter(new FileOutputStream(FILE_LOCATION));
}
catch (FileNotFoundException ex) {
JOptionPane optionPane = new JOptionPane("Unable to write to file\n " + FILE_LOCATION, JOptionPane.ERROR_MESSAGE);
JDialog dialog = optionPane.createDialog("Error!");
dialog.setAlwaysOnTop(true);
dialog.setVisible(true);
System.exit(0);
}
Iterator<YOUR_OBJECT> i = this.List.iterator();
YOUR_OBJECT temp = null;
while (i.hasNext()) {
temp = i.next();
if (temp instanceof YOUR_OBJECT) {
outputStream.println(temp.getAttribute());
}
}
outputStream.close();
I have been trying to load an SQL database into a datatable in C++, however; it doesn't seem to want to work. The connection is working though, as DataReader works. Here is my code
void importDatabase() {
SqlConnection con;
SqlDataAdapter^ da;
SqlCommand cmd;
DataTable^ dt;
int count = 1;
try {
con.ConnectionString = "Data Source=MYNAME\\SQLEXPRESS;Initial Catalog=VinylRecords;Integrated Security=True";
cmd.CommandText = "SELECT * FROM Records";
cmd.Connection = %con;
con.Open();
da = gcnew SqlDataAdapter(%cmd);
dt = gcnew DataTable("Records");
Console::Write(da->ToString());
da->Fill(dt);
for (int i = 0; i < dt->Rows->Count - 1; i++) {
String^ value_string;
value_string = dt->Rows[i]->ToString();
Console::WriteLine(dt->Rows[i]->ToString());
count++;
}
cout << "There are " << count << " many records";
}
catch (Exception^ ex) {
Console::WriteLine(ex->ToString());
}
}
Please note, that I slightly altered the source name to post here, but only the first part.
What is wrong with my code?
So, the problem is here:
dt->Rows[i]->ToString()
Rows[i] is a Row object. And the Row class's ToString() method always prints out the fully qualified typename, which is what you are seeing. So this is technically working just fine. What you will need to do to get something useful is: you will need to access a specific column in that row and get it's value, then output that.
Something along the lines of:
foreach (DataRow dr in dt.Rows)
{
Console.Write(dr.Field<int>("ColumnOne"));
Console.Write(" | ");
Console.WriteLine(dr.Field<string>("ColumnTwo"));
}
I am not entirely sure on the syntax for accessing a specific cell inside of a DataTable when using C++\CLI. So I have provided the C# equivalent to explain why it is you were getting output of managed type names (e.g. "System.Data.DataRow") instead of the info inside of the Row's columns.
Also, I noticed you tagged this question with "mysql", but you are using the ADO.NET System.Data.SqlClient namespace. The SqlDataReader and SqlDataAdapter classes only work with TSQL (Microsoft's SQL Server databases) If you are actually connecting to a mysql database you will want to use the System.Data.OdbcDataAdapter class. You can read a little more here: https://msdn.microsoft.com/en-us/library/ms254931.aspx