How to solve NoClassDefFoundError? - eclipse

Question

I am enrolled in the Duke University course offered by coursera "Java-Programming-Arrays-Lists-and-Structured-data".
I am using Eclipse instead of using BlueJ for my own ease. But when I try to compile the program I get the following error.
Exception in thread "main" java.lang.NoClassDefFoundError: edu/duke/FileResource
I have imported the jar file edu.duke.* and trying to run the program from the main method.
Can someone kindly help how to solve this problem?
import java.lang.*;
import edu.duke.*;
public class WordLengths {
public void countWordLengths (FileResource resource, int[] counts) {
for(String word:resource.words()) {
int wordLength = word.length();
for(int i = 0; i < wordLength; i++) {
char curChar = word.charAt(i);
if((i == 0) || (i == wordLength - 1)) {
if(!Character.isLetter(curChar))
wordLength--;
}
}
counts[wordLength]++;
System.out.println(" Words of length "+ wordLength +" "+ word);
}
}
public void indexOfMax (int[] values) {
int maxIndex = 0;
int position = 0;
for(int i = 0; i < values.length; i++) {
if(values[i] > maxIndex) {
maxIndex = values[i];
position = i;
}
}
System.out.println("The most common word is :"+ position);
}
public void testCountWordLengths () {
FileResource f = new FileResource("C:\\Users\\Ramish-HP\\eclipse-workspace\\Assignment1\\smallHamlet.txt");
int[] counts = new int[31];
countWordLengths(f, counts);
indexOfMax(counts);
}
}
public class WordLengthsTest {
public static void main(String[] args) {
WordLengths wl = new WordLengths();
wl.testCountWordLengths();
}
}

Answer 1

java.lang.NoClassDefFoundError commonly thrown if the Java Virtual Machine or a ClassLoader instance tries to load in the definition of a class (as part of a normal method call or as part of creating a new instance using the new expression) and no definition of the class could be found.
The searched-for class definition existed when the currently executing class was compiled, but the definition can no longer be found.
Reference: https://docs.oracle.com/javase/7/docs/api/java/lang/NoClassDefFoundError.html
I will suggest to check run time libraries.