Layne Lund

Here is a great tutorial that gives step-by-step instructions to create your first Java application. Let us know if you run into any problems and we will be glad to answer your questions.

Layne

Thanks. I figured it out. I'm using Netbeans and it took me to the line in the setUp() method when I double clicked on the JUnit output. No wonder I was confused by that.

Layne

What kind of array are you using? If you have declared an array of ints (int[]), then you CANNOT use null as a value. The null value is only valid for object references. I think this is why you are confused. There is no way to "empty" an array of primitive values (such as int, char, etc.).

Layne

protected void setUp() throws Exception { System.out.println("setUp()"); System.out.println("allowedFile: " + this.allowedFile); this.instance = new AllowedProperty(this.allowedFile); // Line 53 //this.in = null; }

The above code produces output such as

------------- Standard Output --------------- ... setUp() allowedFile: files\ngrams\allowed\0a2.txt ... Testcase: AllowedPropertyTest:files\ngrams\allowed\0a2.txt, a1 (1)(xor.AllowedPropertyTest):Caused an ERROR null java.lang.NullPointerException at xor.AllowedProperty.<init>(AllowedProperty.java:53) at xor.AllowedPropertyTest.setUp(AllowedPropertyTest.java:50)

What could cause a NullPointerException? allowedFile is a File object, and as you can see it is NOT null. Besides, if it was, the AllowedProperty constructor throws a NullPointerException with a custom message:
public AllowedProperty(File allowedFile) throws IOException { if (allowedFile == null) { throw new NullPointerException("allowedFile cannot be null"); } // snip... }
Any ideas why I get a NPE?

For complicated graphics, you should look into Java3D or OpenGL bindings for Java (such as jogl). These libraries provide a lot more tools that you can use other than the simple graphics in the Swing library. I'm willing to bet that most of the C++ samples you see online use OpenGL, so if you use OpenGL in Java, it will probably be easier to translate them over.

I hope this helps.

Layne

Let's say you have data in this table as follows:

id year description -- ---- ----------- 3 1969 asdf 3 1972 jkl;
The query you gave (select a_id, a.description,a.year distinct) will return both of these rows since the ordered triple for each of this rows is different (i.e. at least one column has a different value). "distinct" will only eliminate rows when all three columns have the exact same value. If you want just one row with the id of 3, which of these two rows should be returned?

I apologize that I don't have any suggestions how to solve your problem. I just wanted to help clairfy how "distinct" works in a SQL query.

Layne

Originally posted by Wayne Styles:
Hi
java.lang.NoSuchMethodError: main
Exception in thread "main"

How are you compiling and running this program? From my experience, if you got this message, then your code DOES compile. However, it cannot run because (as the error says) there is no method named "main". You need to create sucha method with the correct signature as marc describes above. Let us know if you need more help.

Layne

Originally posted by colin shuker:
I guess you would extend Applet, if you just wanted to paint directly
to screen, not sure if you can JPanels when extending Applet

Applet is part of the old AWT API. You would use Panel instead of JPanel if you wanted to go this route. However, I think using Swing (all the GUI classes that start with J) is the prefered method in more recent versions of Java.

Layne

How does the user input this integer? Are you creating a console interface or a GUI? All the above will work fine if you are using plain text. However, if you are doing a GUI, you might want to look into using JFormattedTextField.

Layne

Originally posted by Keenan Staffieri:
ok, ty, sorry for all question, but im noob and needed assurace

That's exactly what this forum is for. Please come back with more questions.

Layne

That's a good question. I don't recall one, either. It would be nice to see a book promotion for something about games programming in Java.

Layne

First of all, how much programming experience do you have? What kind of game do you want to make? Games can vary from very simple ones like tic-tac-toe or connect four to more complicated games like chess, go, or Quake. In either case, you need to start by learning a programming language, if you haven't already. From there you can learn about graphics, sound, and all the other details that go into creating a game.

Sorry that I don't have anything more specific than this. Perhaps it will help if you explain what kind of background you have. That will give us a good idea of how to help you go from there.

Layne

Why do you need someone to implement this for you? What kind of list should it iterate over? Do you have some particular project in mind where you need this?

The existence of this class is primarily useful along with the List interface. Notice that it has methods that return ListIterator. If you call any of these methods, you don't have to worry about who the concrete class is that implements this interface. You only need to know that this class certainly implements all the methods required by the ListIterator documentation.

So in the end, if you are using the standard Collections API, you don't need to worry about writing your own class to implement this interface. One exists already. However, if you are writing your own class to implement the List interface, then you probably need to create a companion class that implements ListIterator as well. I don't think someone will just do this for you.

Layne

What is your question?

First of all, you should take a look at this tutorial about Strings and StringBuffers. This should give you a good introduction to the tools available to solve this task. You should also familiarize yourself with the Java API docs. This will give you a handy reference to the classes and methods available from the standard Java API. It is certainly worth your time to learn how to navigate this. For now, you should start by finding the classes in the java.lang package since that is where String and StringBuffer are located.

Layne