Java + Json - ClassNotFoundDefError

Question

I'm trying to get an program that I coded to run properly. So far it will javac and java fine, however I get a NoClassDefFoundError.

This screenshot shows how I've javac, java the program, and the command prompt report. As you can see I have 3 source files, and therefore 3 classes. PeriodicTable doesn't do anything related to the issue.

Inside of class Table I have...

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.json.JsonArray;
import javax.json.JsonObject;

import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.Color;
import java.awt.Toolkit;
import java.awt.Dimension;

import java.io.IOException;

class Table {
    //Predefining some global variables
    DataBaseReader dbReader;
    //some methods...
    protected void showLayout() {
        dbReader = new DataBaseReader();
        //A few lines of code
        try {
            JsonArray elements = dbReader.readDataBase(); //Here it enters the DataBaseReader class through dbReader
            //Some more code
        } catch(IOException ioe) {
            ioe.printStackTrace();
        }
    }
}

Here is my DataBaseReader class

import javax.json.Json;
import javax.json.JsonReader;
import javax.json.JsonObject;
import javax.json.JsonArray;
import java.io.FileReader;
import java.io.IOException;

public class DataBaseReader
{
public JsonArray readDataBase() throws IOException {    
    System.out.println("Check!"); //This check is reached
    JsonReader reader = Json.createReader(new FileReader("C:/projects/PeriodicTable/Elements.JSON"));
    System.out.println("Check!"); //This check is not reached
    JsonObject jsonst = reader.readObject();
    reader.close();
    return jsonst.getJsonArray("Elements"); 
}
}

What versions, programs, etc am I using?

Java 8

Command Prompt

Notepad

javax.json-1.0.jar

To clearly state my question... Any ideas or explanations about what is causing this error?

CBastianelli said something that made think about that again. However, for some reason command prompt can't find the classes unless I use -classpath a second time... Any ideas on how to fix this? — Tyler, Apr 14 '16 at 17:19
You can only launch programs that have a `main()` method via `java` — Bajal, Apr 14 '16 at 17:19
I do have a main method, it's in PeriodicTable class. Also the program compiles and launchs, the NoClassDefFoundError appears during runtime — Tyler, Apr 14 '16 at 17:27
this could help you http://stackoverflow.com/questions/18802098/setting-classpath-using-command-prompt-in-windows-7 — nyname00, Apr 14 '16 at 17:30

score 0 · Answer 1 · answered Apr 14 '16 at 17:18

0

i think you are missing javax.json-api-1.0.jar file

answered Apr 14 '16 at 17:18

Priyamal

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I've used javax.json-1.0.jar and have it successfully worked with previous attempts for this program. (Though for other reasons I had to scrap these attempts) – Tyler Apr 14 '16 at 17:20
can you show the import statements of the class – Priyamal Apr 14 '16 at 17:22
I'll add them to the original post, just need a few minutes – Tyler Apr 14 '16 at 17:24
may be you should build your application then. and try after that – Priyamal Apr 14 '16 at 17:27
The program doesn't reach the end of the current application though, it fails at table.showLayout(); -> JsonArray elements = dbReader.readDataBase(); -> JsonReader reader = Json.createReader(new FileReader("C:/projects/PeriodicTable/Elements.JSON")); I've already tested this, as it does not output the second 'Check!' (See the code in DataBaseReader for Check!) – Tyler Apr 14 '16 at 17:30

Java + Json - ClassNotFoundDefError

1 Answers1