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javastringstringbuilderstringbuffer

Each call to StringBuffer#toString and StrinBuilder#toString returns new instance or instance from string pool?

My question is if am using a StringBuffer(or StringBuilder) and if I call toString method on the instance multiple times. Will StringBuffer return new instance of String each time or it returns String from String pool? ( assuming I have not made any change to StringBuffer in between the calls)

Solution

  • Only string literals are placed in String constant pool. e.g. String s = "abc"; will be in string pool while String s = new String("abc") will not be. toString() method created a new string so the string returned will not be from literal pool.

    Whenever toString() method is encountered, a new String will be created.

    String constant pool objects will be referred once again only if you do as follows. 

    String s = "abc";
String s1 = "abc";

    This means both reference variables s and s1 will refer to same abc literal in the constant pool.

    You can find a useful articles regarding the string constant pool here. http://www.thejavageek.com/2013/06/19/the-string-constant-pool/