I'm writing testcases to select 7 radio buttons. While select the radio button it displays run time error.

I have tried with below code :

    public void selecttemplate()
	{
	 	
		List<WebElement> rdBtn = driver.findElements(By.name("Template_Type"));				
		int size=rdBtn.size();
		
		for(int i=0;i<size;i++)
		{
			String val=rdBtn.get(i).getAttribute("value");
		
			if(val.equals("Documents"))
			{
				rdBtn.get(i).click();
				break;
			}
		}
		WebElement save=driver.findElement(By.name("register-button"));
		save.submit();
    }
Below is error snap:

[![enter image description here][1]][1]


[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/EKz4C.png
  [2]: https://i.sstatic.net/sqQp2.png