Static and Non Static in TestNg - selenium

Question

I have senario where I want to understand use access modifier Static and non static in TestNG. Here is actual code `
public class BaseClass {
public WebDriver driver =null;
public File f = null;
public FileInputStream fs = null;
public static Properties config = null;
private final String configPath="C:\\Users\\prakumak\\eclipse-workspace\\WebDriverTestNGDDFramwork\\src\\MangoHCM\\Config.properties";
#BeforeClass
public void setup() throws Exception {
f = new File(configPath);
try {
fs = new FileInputStream(f);
config = new Properties();
config.load(fs);
}catch(FileNotFoundException e) {
System.out.println(" File is not present");
}catch(IOException e) {
System.out.println("File not loaded");
}
if(config.getProperty("BrowserName").equalsIgnoreCase("Firefox")) {
driver = new FirefoxDriver();
}else if(config.getProperty("BrowserName").equalsIgnoreCase("Chrome")) {
driver = new ChromeDriver();
}else {
throw new Exception("BrowserName is either not mentione OR not correct");
}
}
Scenario 1: When I make Properties variable STATIC and setup() method as NON static, I am still able to call Properties variable in non-static setup() method directly. How could it possible to use static variable in non static method ?
scenario 2: When I make Setup() method as STATIC and Properties variable as non-static then I am getting error saying that "annot make a static reference to the non-static field ". This is OK for me.
Please help me to static how does static and non static work in TestNG? Is it same as normal concept of Java or something is different here? does adding annotation in any menthod in testNG makes it static?

Answer 1

The concept of static and non-static are the same in Java and TestNG.
Non-static always requires a context, referenced by this. Static does not require a context, but you can use the class name. Use of the class name is not required if your code is within that class (i.e. BaseClass.config). The same rule applies for methods (i.e. BaseClass.setup() in your code, unless setup is declared as static).
If you add a non-static setup() method annotated with #Before, you would have two methods, one that requires a context and one that does not. To make your code more readable, i suggest that you rename your static setup() method to setupClass().
Since your method is annotated with #BeforeClass, it has to be static. It is bound to the class and not to a context. This is implicitly required by #BeforeClass.
#BeforeClass requires a static method
#Before requires a non-static method
You can always access field and methods that do not require a context from methods that do require a context. Keep in mind that fields that have no context are shared by static and non-static methods and even between different non-static methods that have a different context.
Basic rule is to stick with the same modifier, either non-static or static, for fields and methods.