override toString

[Rayt Leeop]

Hi, I tried to override toString but got the message: unreachable code. Can anyone help m eon this? Thanks

public String toString(){//override toString()

return "Passengers:" + getP();//P,T,M are get method. I changed it to variable--the return variable in the getter method, doesnot help
return "Tank Capacity:" + getT();///wrong message at this line
return "MPG:" + getM();
}


public static void main(String[] args){

Vehicle details= new Vehicle();
System.out.println(details);
}

[Christopher Nortje]

A method that declares a return type (in your case a String) can only return one value.
You should concatenate the values and return a single String.
The compiler is warning you that the JVM won’t reach the second return statement

return "Tank Capacity:" + getT();///wrong message at this line

because as soon as the first return is reached the execution would stop for that method and return to the caller.
Have a look at java return value.
http://download.oracle.com/javase/tutorial/java/javaOO/returnvalue.html

[Badal Chowdhary]

Rayt,

As Christopher mentioned, you can have only 1 return statement in a method. All code below that would be unreachable because the compiler would not execute anything below return statement.

String objects are immutable. Instead of creating 3 String objects, create 1 StringBuffer object. Append all 3 properties, convert it to String and then return this String.

Thanks,
Badal

[Rob Spoor]

StringBuffer should be avoided; StringBuilder is a better solution. Well, unless you need the synchronization that StringBuffer offers.

If you only concatenate Strings on one single line using an explicit StringBuilder is not necessary though. The compiler will create one for you.

return "Tank Capacity:" + getT();

is currently compiled into this:

return new StringBuilder().append("Tank Capacity:").append(getT()).toString();