How to define an IF statement with AND

I'm passing three values to a function from the main. With these values I make a comparison with an IF statement. The condition has to be that all three parameters have to be verified together, with AND(&&) statement.

This is the main when I pass the values

public static void main(String args[]) {

        start();


        goal();

        load_truck("truck", "cdg", "p1");


    }

This is the function that receive them

public static void load_truck(String truckL, String placeL, String packL) {

        packL = pack;
        truckL = truck;
        placeL = city;
        placeL = airport;
        placeL = loc;


        if(truckL == "truck" && placeL == "cdg" && pack == "p1") {

            at_obj_place(pack = "p1", placeL = "");

            in_pk_vehicle(pack = "p1", truck = "truck");

            System.out.println("\n"+ "The pack "+ pack + " is on the "+ truck );
        }

        if(truckL == "truck" && placeL == "cdg" && pack == "p2") {

            at_obj_place(pack = "p2", placeL = "");

            in_pk_vehicle(pack = "p2", truck = "truck");

            System.out.println("The pack "+ pack + "is on the "+ truck );
        }
        }

The problem is that the comparison with the IF statement is not working. If I insert just one value to compare is working, but with 2 o 3 the IF doesn't work. What is the problem?