String Constant Pool

by

Maybe this will aid your understanding:

String literal = "test";
String one = new String(literal);
String two = "test";

System.out.println(literal == two); //true
System.out.println(one == two); //false

In the example you posted:

String one = new String("test");
String two = "test";

the reference passed to the constructor String(String) has the same value as the reference two due to interning. However, the string itself (referenced by these two references) is used to construct a new object which is assigned to reference one.

In this example, there are exactly two Strings created with the value “test”: the one maintained in the constant pool and referenced whenever you use the literal "test" in an expression, and the second one created by the “new” operator and assigned to the reference one.

Edit

Perhaps you’re confused about this statement:

When the compiler encounters a String literal, it checks the pool to see if an identical String already exists.

Note that this might be more clearly stated as:

When the compiler encounters a String literal, it checks to see if an identical String already exists in the pool.

Strings are only put in the pool when they are interned explicitly or by the class’s use of a literal. So if you have, for example, this scenario:

String te = "te";
String st = "st";

String test = new String(te) + new String(st);

then while a String will exist with the value test, said String will not exist in the pool as the literal "test" has never occurred.

More Related Contents:

  1. String class replace() method [closed]
  2. Can you explain the output of the following source code?
  3. Replace a character at a specific index in a string?
  4. Determine if a String is an Integer in Java [duplicate]
  5. How can a string be initialized using ” “?
  6. Strings are objects in Java, so why don’t we use ‘new’ to create them?
  7. Why StringBuilder when there is String?
  8. Java Replacing multiple different substring in a string at once (or in the most efficient way)
  9. Java String remove all non numeric characters but keep the decimal separator
  10. How do I turn a String into a InputStreamReader in java?
  11. Putting char into a java string for each N characters
  12. Get string character by index
  13. Converting Integer to String with comma for thousands
  14. How to split String with some separator but without removing that separator in Java? [duplicate]
  15. Integer.valueOf() vs. Integer.parseInt() [duplicate]
  16. Get an OutputStream into a String
  17. Why does Java’s concat() method not do anything?
  18. compareTo() vs. equals()
  19. The concatenation of chars to form a string gives different results
  20. Sorting 2D array of strings in Java
  21. Java String Concatenation with + operator
  22. Correct way to use StringBuilder in SQL
  23. Java string searching ignoring accents
  24. How to convert a Binary String to a base 10 integer in Java
  25. How is String in switch statement more efficient than corresponding if-else statement?
  26. What is a good alternative of LTRIM and RTRIM in Java?
  27. Java : Convert formatted xml file to one line string
  28. Is concatenating with an empty string to do a string conversion really that bad?
  29. Create a SortedMap in Java with a custom Comparator
  30. Java replace all square brackets in a string

Leave a Comment