new String("text");
explicitly creates a new and referentially distinct instance of a String object; String s = "text"; may reuse an instance from the string constant pool if one is available.
You very rarely would ever want to use the new String(anotherString) constructor. From the API:
String(String original): Initializes a newly createdStringobject so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of original is needed, use of this constructor is unnecessary since strings are immutable.
Related questions
- Java Strings: “String s = new String(”silly“);”
- Strings are objects in Java, so why don’t we use ‘new’ to create them?
What referential distinction means
Examine the following snippet:
String s1 = "foobar";
String s2 = "foobar";
System.out.println(s1 == s2); // true
s2 = new String("foobar");
System.out.println(s1 == s2); // false
System.out.println(s1.equals(s2)); // true
== on two reference types is a reference identity comparison. Two objects that are equals are not necessarily ==. It is usually wrong to use == on reference types; most of the time equals need to be used instead.
Nonetheless, if for whatever reason you need to create two equals but not == string, you can use the new String(anotherString) constructor. It needs to be said again, however, that this is very peculiar, and is rarely the intention.