Need some help with Java code

Question

import java.util.Scanner;

public class pomodoro_timer {
public static void main(String args[]){
Scanner input = new Scanner(System.in);
try {
System.out.print("\nPress \'Enter\' to start or OR Type \'quit\' to quit the program: ");
String start = input.nextLine();
if(start==""){
System.out.print("yes");
} else if(start=="quit"){
System.out.print("no");
} else{
System.out.print("\nINVALID INPUT. TRY AGAIN");
main(args);
}
}
finally {
input.close();
}
}
}

It always executes the "else" statement. What's wrong with it? Thanks in advance.

Answer 1

The == operator in Java checks for reference equality: it returns true if the pointers are the same. It does not check for contents equality. Identical strings found at compile-time are collapsed into a single String instance, so it works with String literals, but not with strings generated at runtime.

For instance, "Foo" == "Foo" might work, but "Foo" == new String("Foo") won't, because new String("Foo") creates a new String instance, and breaks any possible pointer equality.

More importantly, most Strings you deal with in a real-world program are runtime-generated. User input in text boxes is runtime-generated. Messages received through a socket are runtime-generated. Stuff read from a file is runtime-generated. So it's very important that you use the equals method, and not the == operator, if you want to check for contents equality.

Answer 2

@Vahagn Lazyan , thank you!

Answer 3

This is why Python is much more attractive than Java. (Because I've never had silly problems like this with Python).