CODEWITHSUNDEEP
javaobjectnullboolean
Templar
Templar

Reputation: 1871

Java prints "null" for String reference != to null

I have big code and such lines:

System.out.println(car.getName());
System.out.println(car.getName() == null);

First line print outs: null

but second line print outs false, so null == null is false?

I have also tried System.out.println(car.getName() == "null"); since getName returns String but same result

Upvotes: 3

Views: 1693

Answers (3)

love__coder
love__coder

Reputation: 11

The result is "null"， not null, so your code will be: 

System.out.println(car.getName().equals("null"));

Upvotes: 1

talnicolas
talnicolas

Reputation: 14053

When it comes to String you need to use the equals method:

System.out.println("null".equals(car.getName());

if it actually returns the String "null" which is not the same as null.

Why using equals instead of ==, I can't find a simpler explanation than this one:

To compare Strings for equality, don't use ==. The == operator checks to see if two objects are exactly the same object. Two strings may be different objects, but have the same value (have exactly the same characters in them). Use the .equals() method to compare strings for equality.

Upvotes: 4

Richard J. Ross III
Richard J. Ross III

Reputation: 55533

If I had to guess, your code has something like this in it:

public String getName()
{
    return "null"; 
}

So, when you run your test,

System.out.println(car.getName() == null);

It is testing the string object "null" with the value null, which is indeed false.

Upvotes: 1

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