Getting error while compiling extension

[Nitish_Rajput]

Hello Extension developers,
I am newbie in extension development. today i am trying to create my 1st extension but i am getting error when compiling.

Here is error code

I am using IntelliaJ Idea to create extension.

My java code
package com.hello.myextension;
import com.google.appinventor.components.annotations.DesignerComponent;
import com.google.appinventor.components.annotations.SimpleObject;
import com.google.appinventor.components.annotations.SimpleFunction;
import com.google.appinventor.components.annotations.SimpleEvent;
import com.google.appinventor.components.annotations.SimpleProperty;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.runtime.AndroidNonvisibleComponent;
import com.google.appinventor.components.runtime.AndroidViewComponent;
import com.google.appinventor.components.runtime.ComponentContainer;
import com.google.appinventor.components.runtime.EventDispatcher;

@DesignerComponent(version = 1,
category = ComponentCategory.EXTENSION,
description = "",
nonVisible = true,
iconName = "")

@SimpleObject(external = true)

public class myextension extends AndroidNonvisibleComponent {

public myextension(ComponentContainer container) {
    super(container.$form());
}

@SimpleFunction(description = "Simple addition of two numbers")
public int Add(int a, int b) {
    return a + b;

}

}

[pavi2410]

Do you have git installed?

[Nitish_Rajput]

@pavi2410

git

@shreyash said it's not necessary so i haven't installed

[vknow360]

It seems you will have to install it at least for first compilation.
After that you can uninstall Git.

[shreyash]

I never said that. You asked if Git Bash is necessary, and I told you that it's optional and any terminal would work.

[White_Tiger]

I also followed syresh's method without git using visual studio its working fine

[Nitish_Rajput]

Thanks to @pavi2410,@vknow360 and @shreyash I just installed Git Bash and now my problem is solved