WebElement ELR = driver.findElement(By.id("trades-list"));
List<WebElement> list = driver.findElements(

String[] tradeId = null; 
for(int i = 0; i < list.size(); i++ )
    String str = list.get(i).getAttribute("id");
    tradeId[i] = str.substring(23);

str will contain following list is the output of String str = list.get(i).getAttribute("id");


Here I want to print 92222, 93333, 94444 in the string tradeId.

I am getting the following error message:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -4 at java.lang.String.substring(Unknown Source) at com.traderev.selenium.multipleBrowser.main(multipleBrowser.java:71)

  • Glad to have helped. If your question is solved, you should accept Niels' answer. It answers the original question of copying substrings very nicely. Apr 23, 2015 at 18:04

2 Answers 2


How do you come to 23 in tradeId[i] = str.substring(23);, your strings like trade-summary-92222 are only 19 characters long, not?

19 - 23 = -4, which is what your errors says its can't find the last 4 characters.

For readability and a partial string you could use: public String substring(int beginIndex, int endIndex)

Your code would become:

tradeId[i] = str.substring(19-5, 19);

Or try just this to get the last five

tradeId[i] = str.substring(str.length() - 5);

Or to prevent the exception if the string becomes shorter then 5

tradeId[i] = str.substring(Math.max(0, text.length()-5)); 

Or this

tradeId[i] = str.substring(s.lastIndexOf('-') + 1);
  • I tried the above method but now getting exception as Total count is3 trade-summary-92195 Exception in thread "main" java.lang.NullPointerException at com.traderev.selenium.multipleBrowser.main(multipleBrowser.java:73)
    – Monika
    Apr 21, 2015 at 14:05

You are getting a nullpointer exception because you're trying to assign values to index locations in a null array.

This statement

String[] tradeId = null; 

should be

String[] tradeId = new String[list.size()]; 

so when you later do this:

tradeId[i] = str.substring(s.lastIndexOf('-') + 1);

There will be a space in the array reserved for that value.

Hope that helps!


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