Thread: Off topic I know (Java Question)

I came here because this place seems to have the most knowledgeable programmers on the internet

My question is: In java if everything is essentially an object (aside from primitive data types), including Strings, why do you have to return a String back to main if you want to make some changes to it. example

Code:

//your main class
main
{
String s = "C programming";
StringChangerObject o = new StringChangerObject();
o.changeString(s);
print(s);
}

//another class in a different file
StringChangerObject{
public void changeString(String blah){ blah = "Java programming"; }
}

I know this is a terrible example and I left out details in the code, im just trying to paint a picture here and get the underlying reason as to why that wont work if a String is an object.

Perhaps maybe that method goes on the stack and since the parameter is on the stack as well, when the method ends, the stack pointer erases all that has to do with that method????

IDK im confuseddddd

First, you should bother to post an example that has all the details and isn't terrible.

Second, you should research this yourself first, and then ask us for help if you're still stuck. If you did research this, you certainly didn't indicate it. Try searching "java string tutorial". The first result is this: Strings (The Java™ Tutorials > Learning the Java Language > Numbers and Strings). Read the "Note" section.

Originally Posted by new2C-

why do you have to return a String back to main if you want to make some changes to it.

I don't know Java, but my guess would be because your assignment of "blah" is creating a new object. Java is pass-by-value, so your callee never gets to see the assignment of the argument.