About Question enthuware.ocajp.i.v7.2.1392 :

[admin]

Please read the explanation carefully. It is correct. It is talking about a different case. Had newStre been defined as String newStre = ""...

[vandreev]

all the chars will be concatenated to null, so newStr = nullgood in the end

[st.lisker]

String myStr = "good";
char[] myCharArr = {'g', 'o', 'o', 'd' };

System.out.println(myStr == "good");

String newStr = "";
for(char ch : myCharArr){
newStr = newStr + ch;
}

System.out.println("_____________________________");
System.out.println(newStr.hashCode()); //3178685
System.out.println(myStr.hashCode()); //3178685
System.out.println(newStr==myStr); // false -------------> But why?

The explanation says that these are two different objects, but why? There was not new(). They are put in the pool. They even have the same hash code. Why the false?

[admin]

Just because the hashCodes of two objects are equal doesn't mean that the objects themselves are equal. (There reverse is actually true i.e. if the objects are equal then the hashCodes will be equal).
A String created using concatenation where its operands are not compile time constants is a new String.

[st.lisker]

Thanks for the answer!
"Just because the hashCodes of two objects are equal doesn't mean that the objects themselves are equal." -> I thought, it means that they are the same object 8-(
"A String created using concatenation where its operands are not compile time constants is a new String" -> OK, got it (This point can be on the exam? )

[admin]

>This point can be on the exam?
Yes, it is possible but most probably not.

[rali14043]

This is a bug in Java since If I write the following line they don't compile:

String newStr = null (compiles successfully)
String newStr1 = Null (does not compiles)
String newStr2 = NULL (does not compiles)
String newStr3 = abcd (does not compiles)

I don't understand while String newStr = null compiles while any other values don't compile.

[admin]

Java is case sensitive. null is a keyword but Null and NULL are not. Neither is abcd. So, the compiler thinks that Null, NULL, and abcd are variable names.

Also, pay close attention to the error message. It will tell you exactly what the compiler is thinking.

Are you following any book?

[itvase]

Did something go wrong here?

Look for correct/green answer and the explanation:

and true for newStr.equals(myStr)

I have the same concern as you.
It's strange that admin hasn't responded to this for more than 7 years.

[admin]

Did something go wrong here?

Look for correct/green answer and the explanation:

and true for newStr.equals(myStr)

I have the same concern as you.
It's strange that admin hasn't responded to this for more than 7 years.

The reply to this query is there at the top of this page.
I am not sure what is the issue.