A Run question.

[nomad]

I have a question in which I want to run my java program.
I'm using Eclipse as my application.
When I want to run my program I do a right-click on the mouse and choose
Run as (arrow down to) run...
A Window called Run shows on the screen.
In the Main class: I have a chose to make by pushing the Search...button
In doing so I have a list of options to chose from.
Matching types which has my project (Employee) or there is another on
under ----Workspace matches------ which again it is listed (Sometimes it listed)

Question is which one do I use. I get an Erros in Project Window.
Erros exist in required Project.FirstJa vaProject.
Contune launch?
I can not figure out where the errors are at considering I'm usign Eclipse.



thanks
damon
PS no matter which one I use I get an error.

[JosAH]

When you navigate to Window > Show View > Problems you can see details
of all problems in all open projects. Click on one of the problems and Eclipse
will open the corresponding source for you. Note that the left border of every
source show you the lines which contain errors. If you move your mouse over
those little icons you get a nice description of the error again.

kind regards,

Jos

[nomad]

Thanks Jos...
I did what you told me to do...
the error was listed as
java.lang.NoSuc hMethodError: main
Exception in thread "main"

How do I go about find out how to fix this error.
Do you need me to post my code....

thanks
nomad

[JosAH]

Thanks Jos...
I did what you told me to do...
the error was listed as
java.lang.NoSuc hMethodError: main
Exception in thread "main"

How do I go about find out how to fix this error.
Do you need me to post my code....

thanks
nomad

The JVM (Java Virtual machine) always starts one of your classes by calling
the public static void main(String[] args) method in that class. In your case
that particular class doesn't contain such a method (NoSuchMethodEr ror: main)

You have to define that method.

kind regards,

Jos

[nomad]

that's what I thought it meant.
but I have this at the end of my project...

Thanks
nomad
ps is this right....
The rest of the projecgt is done with one class, one public class and severl public void...

	public static void main(String[] args) {

		Employee_listing employeelist = new Employee_listing();
		Scanner input_flag = new Scanner(System.in);

		int choice;
		System.out.println("Make a Section: ");
		System.out.println("1. Enter ");
		System.out.println("2. Find ");
		System.out.println("3. Exit ");
		System.out.print("\nPlease press Enter afer each response");
		System.out.println("Enter your chose please: ");
		choice = input_flag.nextInt();
		input_flag.nextLine();
		if (choice == 1) {// if 1 is select go to makePerson
			employeelist.inputEmployee();
		}// close the if loop
		if (choice == 2) {// if 2 is select go to find
			employeelist.displayMatch();
		}
		if (choice == 3) {
			System.out.printf("Good bye");
		}// close if loop

	}// close public static void

[JosAH]

Eclipse uses "launch configurations" to start your Java programs. Navigage
to Run > Run ... and select "Java Application" next press the "new launch"
button at the top left. Then that big dialog comes up; name your new config,
specify the project, the name of the class that contains the main method;
click "apply" and then run your program.

Note that you can have different launch configurations and you can define
new ones for every open project in your workspace.

kind regards,

Jos

[nomad]

Thanks Jos...
I figure it out with your info.
I'm very new to Java and my instructor is not very helpful that goodness for sites like this one.
Your suggestion did not work, until I created a new Prpject. I then moved my Package to the new Project.
But now I get a new error:
Exception in thread "main" java.lang.NullP ointerException
at company.Employe e_listing.displ ayMatch(Employe e_listing.java: 223)
at company.Employe e_listing.main( Employee_listin g.java:272)

Note I have a Array and Arraylist.
Any ideal how I can solve this problem

This is my Arraylist

	public void createEmployeeDatabase() {
		Employees = new ArrayList<Employee>();

	}

thanks again
nomad

[r035198x]

Thanks Jos...
I figure it out with your info.
I'm very new to Java and my instructor is not very helpful that goodness for sites like this one.
Your suggestion did not work, until I created a new Prpject. I then moved my Package to the new Project.
But now I get a new error:
Exception in thread "main" java.lang.NullP ointerException
at company.Employe e_listing.displ ayMatch(Employe e_listing.java: 223)
at company.Employe e_listing.main( Employee_listin g.java:272)

Note I have a Array and Arraylist.
Any ideal how I can solve this problem

This is my Arraylist

	public void createEmployeeDatabase() {
		Employees = new ArrayList<Employee>();
 
	}

thanks again
nomad

Can you post the code for the displayMatch method and indicate which line is line 223?

[JosAH]

Thanks Jos...
I figure it out with your info.
I'm very new to Java and my instructor is not very helpful that goodness for sites like this one.
Your suggestion did not work, until I created a new Prpject. I then moved my Package to the new Project.

Good; may I suggest that you remove the old project including all its resources?
It avoids cluttering you harddisk and cluttering Eclipe's workspace.

But now I get a new error:
Exception in thread "main" java.lang.NullP ointerException
at company.Employe e_listing.displ ayMatch(Employe e_listing.java: 223)
at company.Employe e_listing.main( Employee_listin g.java:272)

Note I have a Array and Arraylist.
Any ideal how I can solve this problem

That is also good: it shows that Eclipse can run your project. All you have to
do now is solve your bug ;-)

Navigate to Run > Debug; select your project and select the button "stop in main".
Next Eclipse will switch to its "debugging perspective" where you van step
every single statement of your code; hint: F7 steps over an entire method
while F5 steps "into" the method. Give it a try and experiment with it all a bit.

Pay special attention to the little panel at the top right corner; it displays the
values of all variables in scope.

kind regards,

Jos

[r035198x]

Good; may I suggest that you remove the old project including all its resources?
It avoids cluttering you harddisk and cluttering Eclipe's workspace.



That is also good: it shows that Eclipse can run your project. All you have to
do now is solve your bug ;-)

Navigate to Run > Debug; select your project and select the button "stop in main".
Next Eclipse will switch to its "debugging perspective" where you van step
every single statement of your code; hint: F7 steps over an entire method
while F5 steps "into" the method. Give it a try and experiment with it all a bit.

Pay special attention to the little panel at the top right corner; it displays the
values of all variables in scope.

kind regards,

Jos

Now that you've said it I think that is actually much better than having him post the code.

[JosAH]

Now that you've said it I think that is actually much better than having him post the code.

I saw those big line numbers and just went *eeew!* Nobody wants to plough
through that much of code; Eclipse itself doesn't care though ;-)

kind regards,

Jos

[nomad]

Can you post the code for the displayMatch method and indicate which line is line 223?

line 223 is
for (Employee e : Employees) {

sure here is my code

public void displayMatch() {
		String id_flag = "";
		Scanner input_flag = new Scanner(System.in);
		System.out.println("Enter your chose please AB1234: ");
		id_flag = input_flag.next();
		boolean notfound = true;
		for (Employee e : Employees) {
			String emp = e.getEmpId();
			if (emp.equals(id_flag)) {
				System.out.println("Hello" + ("e.lname"));
				notfound = false;
			}
		}
		if (notfound == true) {
			System.out.println("Error - Employee not found");
// back to menu?
}// need to find out if this needs to go below printing

I would like help and at the same time I'm going to look into Jos suggestion.

thanks
nomad

[nomad]

Question for you...
I have no data in the arraylist. Does this matter.

nomad

[JosAH]

I would like help and at the same time I'm going to look into Jos suggestion.

thanks
nomad

Degugging is an art form; first press the F6 key continuously; somewhere in
your code that null pointer exception is thrown. Restart your debug session
again (see my previous reply) but instead of stepping *over* that last method
that threw the Exception, step *into* it (using the F5 key). Rinse and repeat
until you've nailed the statement that caused the error.

kind regards,

Jos

[r035198x]

line 223 is
for (Employee e : Employees) {

sure here is my code

public void displayMatch() {
		String id_flag = "";
		Scanner input_flag = new Scanner(System.in);
		System.out.println("Enter your chose please AB1234: ");
		id_flag = input_flag.next();
		boolean notfound = true;
		for (Employee e : Employees) {
			String emp = e.getEmpId();
			if (emp.equals(id_flag)) {
				System.out.println("Hello" + ("e.lname"));
				notfound = false;
			}
		}
		if (notfound == true) {
			System.out.println("Error - Employee not found");
// back to menu?
}// need to find out if this needs to go below printing

I would like help and at the same time I'm going to look into Jos suggestion.

thanks
nomad

But you should know by now where the problem is.