Error with return in Java?

Question

I get an error in the code from this part of my code:

public boolean findCustomer(String inPersonalNumber){

    // check if personal number already exist
    for (int i=0; i<customerList.size();i++) {
        if(customerList.get(i).getCustomerPersonalNumber().equals(inPersonalNumber)){
            return true;
        }
    }
    return true;    
}

When I remove the first return true and instead to the last return true, it don't get the error in my eclipse code, but why can't I have the first place and would this be the same? Thanks!

EDIT: The error message from eclipse say: This method must return a result of type boolean. I'm confused because isn't that what I have done?!

Yes, a break must be in the code

Can I write the method in some other way?

EDIT NUMBER 2
Why isn't this code working?

public boolean findCustomer(String inPersonalNumber){

// check if personal number already exist
for (int i=0; i<customerList.size();i++) {
    if(customerList.get(i).getCustomerPersonalNumber().equals(inPersonalNumber)){
            return true;
        }
        else {
            return false;
        }
    }
}

This method returns a boolean value so I don't understand why I get an error!? The code looks right to me?

Answer 1

Your edit #2 doesn't compile because there is a possibility that your code won't enter the for-loop. This will be the case if customerList.size() is 0. To fix this, you'll simply need to add a return statement after the for-loop as well:

// check if personal number already exist
for (int i=0; i<customerList.size();i++) {
    if(customerList.get(i).getCustomerPersonalNumber().equals(inPersonalNumber)){
        return true;
    }
    else {
        return false;
    }
}
return false;

Another point here is that this code doesn't logically make much sense: it will only return true or false based on the first item in your list. And this is probably not what you want. So take a closer look at several of the other answer here, many of which are good examples for how you can do this.

Answer 2

Looks like you have turned off the Build Automatically feature of eclipse. It maybe complaining about an error that used to be present when you still hadn't typed in your code fully! This can also happen if you have back-dated your system for some reason.

Also, shouldn't you be returning false if the condition doesn't satisfy?

public boolean findCustomer(String inPersonalNumber) {

    // check if personal number already exist
    for (int i = 0; i < customerList.size(); i++) {
        if (customerList.get(i).getCustomerPersonalNumber().equals(inPersonalNumber)) {
            return true;
        }
    }

    return false;
}

Answer 3

public boolean findCustomer(String inPersonalNumber){
    boolean result = false;
    // check if personal number already exist
    for (int i=0; i<customerList.size();i++) {
        if(customerList.get(i).getCustomerPersonalNumber().equals(inPersonalNumber)){
            result = true;
            break;
        }
    }
    return result ;    
}

Answer 4

First return will return only in case of all conditions satisfied, but this method should be returning boolean as per code. It would be expecting a return in failure case also.

Removing first return won't affect compilation as it has a return in second place which will work without any condtions.

Edit : Answer for your second question

This code has two return's, but what if your customerList is size 0, in that case also, method must return boolean. right? for that only, compiler is asking.

BTW, code doesn't have null checks.

Your final code could be this. Keeping multiple return statements in code in not a good practice.

public boolean findCustomer(String inPersonalNumber) {
    boolean retVal = false;
    if (!(inPersonalNumber == null || inPersonalNumber.trim().equals("")
         || customerList == null || customerList.size() == 0)) { // inputs are valid to run this check
         // check if personal number already exist
        for (int i = 0; i < customerList.size(); i++) {
            if (inPersonalNumber.equals(customerList.get(i).getCustomerPersonalNumber()) { // to avoid NPE, kept inPersonalNumber in check 
                retVal = true;
                break;
            }
        }
    }
    return retVal;    
}

Answer 5

When I remove the first return true and instead to the last return true, it don't get the error in my eclipse code, but why can't I have the first place and would this be the same?

If you remove the second return statement the code would be able to run and not return a value - this is not possible as you defined the method to have a return type of Boolean. So it must always return a value no matter what.

Just change the second return statement to false, should do what you want.

Answer 6

Because your for loop looses meaning if you're returning true anyway.
If you want to stop loop use break; instead of first return.