Extracting the initial characters from a string in one go

Question

please advise below is the code to extract the first 4 characters from the string as shown below..

String external = ak.getReference();    
String s= external.substring(0,4);

Can I wrap this into one so that no extra String s need to be created and finally string external will have four initial characters in one go

By extra String, do you mean extra String reference, or String object? Later is not possible. — Rohit Jain, Sep 24 '13 at 14:57

score 3 · Answer 1 · edited May 23 '17 at 10:31

3

Well, you can always chain the method calls...

String s = ak.getReference().substring(0,4);

... But that doesn't mean that an extra string won't be created, starting with Java 7u6 the substring() method will return a new String object with a freshly allocated char[] (see this post). You're just eliminating an intermediate local variable, that's all.

edited May 23 '17 at 10:31

Community

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answered Sep 24 '13 at 14:56

Óscar López

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score 0 · Answer 2 · answered Sep 24 '13 at 14:58

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Same strings are going to be created no matter what. Compiler will optimize that anyways. Otherwise the comment of @ZouZou is correct.

String external = ak.getReference().substring(0,4);

answered Sep 24 '13 at 14:58

akostadinov

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Extracting the initial characters from a string in one go

2 Answers2