Java Code - ArrayIndexOutofBoundsException - math

Question

I have written the following code and keep running into this error:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at yournamep3.Yournamep3test.main(Yournamep3test.java:23)
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
public class Yournamep3test {
public static void main(String[] args) {
// Check if target file exists
File targetFile = new File(args[0]);
try {
PrintWriter out = new PrintWriter(targetFile);
out.write("\r\nStringed musical Instrument program");
for (int arrayIndex = 0; arrayIndex < 10; arrayIndex++) {
out.write("\r\n\r\n");
out.write("\r\nCreating new Stringed Musical Instrument object now..............");
Yournamep3 violinInstrument = new Yournamep3();
violinInstrument.setNameOfInstrument("Violin # " + (arrayIndex+1));
out.write("\r\nCreated instrument with name - "
+ violinInstrument.getNameOfInstrument());
int num = violinInstrument.getNumberOfStrings();
out.write("\r\nNumber of strings in instrument is " + num);
out.write("\r\nNames of String are ");
String strings[] = violinInstrument.getStringNames();
for (int counter = 0; counter < num; counter++) {
out.write("\r\n" + strings[counter]);
}
out.write("\r\nIs the Instrument playing - "
+ violinInstrument.isPlaying());
out.write("\r\nIs the Instrument tuned - "
+ violinInstrument.isTuned());
out.write("\r\nTuning now.........");
violinInstrument.setTuned(true);
out.write("\r\nIs the Instrument tuned - "
+ violinInstrument.isTuned());
out.write("\r\nCalling the Instrument play method now..");
violinInstrument.startPlayInstrument();
out.write("\r\nIs the Instrument playing - "
+ violinInstrument.isPlaying());
out.write("\r\nStopping playing of instrument..............");
violinInstrument.stopPlayInstrument();
out.write("\r\nIs the Instrument playing - "
+ violinInstrument.isPlaying());
}
out.close();
} catch (IOException e) {
}
}
}
I think the issue is with line 23. Any advice would be appreciated, thanks.
This is the other part of the code yournamep3
public class Yournamep3 {
//fields to determine if the instrument is isTuned,
private boolean isTuned;
//and if the instrument is currently isPlaying.
private boolean isPlaying;
private String name;
private int numberOfStrings = 4; // number of strings
private String nameofStringsInInstrument[] = {"E", "C", "D", "A"}; //an array of string names
//A constructor method that set the isTuned and currently isPlaying fields to false.
public Yournamep3() {
this.isTuned = false;
this.isPlaying = false;
}
/**
* #return the name
*/
public String getNameOfInstrument() {
return name;
}
/**
* #param name the name to set
*/
public void setNameOfInstrument(String nameOfInstrument) {
this.name = nameOfInstrument;
}
// Other methods
public boolean isPlaying() {
return isPlaying;
}
public void setPlaying(boolean playing) {
this.isPlaying = playing;
}
public boolean isTuned() {
return isTuned;
}
public void setTuned(boolean isTuned) {
this.isTuned = isTuned;
}
public void startPlayInstrument() {
System.out.println("The Instrument is now Playing.");
isPlaying = true;
}
public void stopPlayInstrument() {
System.out.println("The Instrument is not Playing anymore.");
isPlaying = false;
}
public void startTuneInstrument() {
System.out.println("The Instrument is Tuned.");
isTuned = true;
}
public void stopTuneInstrument() {
System.out.println("The Instrument is not Tuned.");
isTuned = false;
}
public int getNumberOfStrings() {
return this.numberOfStrings ;
}
public String[] getStringNames() {
return nameofStringsInInstrument;
}
}

Answer 1

I would look at your getStringNames() method for your violinInstrument. It seems to me that it isn't populating your String array properly, or the getNumberOfStrings() method does not give the right number of strings. If you put the code for that up, I can help a bit more.

Answer 2

Line 23 appears to be
Yournamep3 violinInstrument = new Yournamep3();
If that's the case you should check the constructor for Yournamemp3
Since Line 23 is
File targetFile = new File(args [0]);
It indicates that your args object is empty. ArrayIndexOutOfBoundException is thrown to indicate that an array has been accessed with an illegal index. 0 is an illegal index.