StringLiteralNoObject

Misconception:

To get a String object with a given value (e.g., "Hello"), one needs to use the String constructor, like so: new String("Hello").

One needs to call the String constructor to get a String object from a literal

A String literal represents a String object and can be treated as such

All the following three statements are correct.

String s1 = "Hello";
String s2 = new String("Hello");
String s3 = new String(new String("Hello"));

However, the second statement uses "Hello", which already refers to a String object, as an argument to the String(String original) constructor, which copies the passed in String. Thus, it unnecessarily creates a copy of the original String literal.

The third statement is even worse: it creates a copy of "Hello", and then it creates a copy of that copy. That’s two unnecessary object allocations.

Novice students may write code like this:

public class Contact {
  private String name = new String("Duke"); // unnecessary wrapping
  private Address address = new Address("1 Java Way");
  //...
}