.equals vs ==

[golden dome]

Ok so far i read that, == doesnt work because it may compare differences "references", not the actual value. So we use .equals

Alright this is clear but... why does this hold only for Strings? why not integers?

[dull saffron]

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[raw geyser]

Bcs String isn't a primitive datatype, whereas int is

char, float, double, short, byte, boolean, long are also primitive

I'd advice you to have a look a the basics of object oriented programming to understand what references are in this context. Then you'll also see, that (and why) something like:

int i = 33;
System.out.println(i.equals(78));

Is actually impossible^^

[dull saffron]

A single equal sign is used for assignments. int value = 5;. For comparing primitves you use two equal signs if (value == 5) and for Objects .equals() if (string.equals(otherString).

[long cargo]

some comment here too

[raw geyser]

Pfffff😂

[long cargo]

ez

[bronze mango]

In the statement

String s = "foo";`

• s is a variable of type 'String reference', not a String object.
• "foo" is a String literal whose type is a 'String reference'.

In Java, the values of parameters, variables, fields and values returned from methods always either primitive values or references.

Since == compares the values, it actually behaves exactly the same for all types.

When you say a.equals(b), the . operator follows the reference in a and invokes the equals method on that object.

When the value in a is null (not referring to an object) then you get an error trying to follow that reference.

[final barn]

It doesn't hold solely for strings but it's a bit worse with Strings compared to other objects

primitives don't have an equalss method, conparing those with == is fine

For other objects: == compares references and equals allows the class to define a different mechanism for comparison (typically a logical comparison taking account the data) so if you want to use that, you should use equals

With Strings, there is no good reason to use ==, especially because of interning.

[final barn]

to avoid the NPE of a.equals(b), Objects.equals(a,b) is an option

[golden dome]

oh lol language differences

in js, string is also primitive

oka it clears up

thank you everyone

[dull saffron]

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