问题:

when a variable is initialize both in local scope as well as global scope how can we use global scope without using this keyword in the same class?

回答1:

class MyClass{
    int i;//1
    public void myMethod(){
        i = 10;//referring to 1    
    }

    public void myMethod(int i){//2
        i = 10;//referring to 2
        this.i = 10 //refering to 1    
    }    
}

Also See :

Shadowing Declarations
what-is-variable-shadowing-used-for-in-a-java-class

回答2:

If you do not use this it will always be the local variable.

回答3:

It is impossible without this. The phenomenon is called variable hiding.

回答4:

If you are scoping the variable reference with this it will always point to the instance variable.

If a method declares a local variable that has the same name as a class-level variable, the former will 'shadow' the latter. To access the class-level variable from inside the method body, use the this keyword.

回答5:

public class VariableScope {

    int i=12;// Global
    public VariableScope(int i){// local

        System.out.println("local :"+i);
        System.out.println("Global :"+getGlobal());
    }
    public int getGlobal(){
        return i;
    }
}