How to use return value from method in Java?

I want to use the return value from a member function by storing it into a variable and then using it. For example:

public int give_value(int x,int y) {
int a=0,b=0,c;
c=a+b;
return c;
}

public int sum(int c){
System.out.println("sum="+c);
}

public static void main(String[] args){
obj1.give_value(5,6);
obj2.sum(..??..); //what to write here so that i can use value of return c
//in obj2.sum
}