Selenium Dataprovider returns a NegativeArrayException when called from different class

Question

I have an excel, which contains multiple worksheets in it. Each worksheet contains multiple columns. I have a class like this.

public class dptwo extends dpone {

@Test(dataProviderClass = testdp.class, dataProvider = "dp")
 public static void methodone(String a, String b , String c)
 {
     System.out.println(a);
     System.out.println(b);
     System.out.println(c);
  }

Now I have another class, in the same package named testdp.java

public class testdp{ 
@DataProvider(name="dp")
public Object[][] getData(Method m) {

String sheetName = m.getName();
int rows = excel.getRowCount(sheetName);
int cols = excel.getColumnCount(sheetName);
Object[][] data = new Object[rows - 1][cols];
    for (int rowNum = 2; rowNum <= rows; rowNum++) { 
             for (int colNum = 0; colNum < cols; colNum++) {
        data[rowNum - 2][colNum] = excel.getCellData(sheetName, colNum, rowNum); 
    }
}
return data;

}

When I run, I'm getting an error as mentioned below.

 [ERROR] [Error] java.lang.NegativeArraySizeException
at temp.dpthree.getData(dpthree.java:18)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:74)
at org.testng.internal.MethodInvocationHelper.invokeMethodNoCheckedException(MethodInvocationHelper.java:45)
at org.testng.internal.MethodInvocationHelper.invokeDataProvider(MethodInvocationHelper.java:131)
at org.testng.internal.Parameters.handleParameters(Parameters.java:706)

However:

If I run both the Data provider and the method from same class it works fine.

I have changed the classname to make it more meaningful names.

Answer 1

you are getting the exception because somewhere you are creating a array with negative size

On analyzing the code , the most possible line that causes this issue would be:

Object[][] data = new Object[rows - 1][cols];

In your code you are getting sheet name as :

String sheetName = m.getName();

When you call this from a different class i am not sure whether the class name will be appended along with the method name eg class.M1 ,

So just print row number and sheetName for debugging purpose and see whether this is causing the issue.

if the name "class.M1" is causing the issue , then split the string and get only the method name. Or see if there is other methods that will give only give method name.