Can't find the error in my java

Question

Simple calculator
https://code.sololearn.com/cL3efUn15iDR/?ref=app

Answer 1

Calculator:

👉 AS SAID BEFORE:
1. Don't import things you do not use, e.g. your line 3

👉 AS SAID BEFORE:
2. Do not put random blank spaces in methods, e.g. it's
System.out.println("something")
not
System. out.println ("something")

3. Write the method names correctly: It's .nextDouble() and .nextLine()...

4. Do not compare strings with == but with the .equals() method

Answer 2

Can't understand num 4

Answer 3

Please explain

Answer 4

Remember that strings are not a primitive type in Java, like integers or characters. String are objects. When you compare two objects with '==', it will compare those objects' memory adresses, not their values.

Answer 5

Ok i understand that
Now how can i write it

Answer 6

Choice.equals("+")
Alternatively you can use .nextChar() instead of .nextLine() and compare values as you're used to