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String equality
Try to predict the result of the following code.
String s = "test";
System.out.println(s.equals("test"));
System.out.println(s == "test");
System.out.println(s == new String("test"));
I think the result of s.equals("test")
is obvious. Yes, it's true
(I mean result).
But the result of s == "test"
is also true
. Because all String
objects are immutable,
before creation of new String
Java looks at pool and tries to find the creating string. If it founds, it
sets reference of found string to variable. Java does it to save memory. That's why the equality s == "test"
is true
.
The equality check s == new String("test")
returns false
because in this case we force Java
to create a new instance of String
object.
Author: Jafar N.Aliyev (Jsoft)
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