Java instanciation syntax explanation

Asked Jun 01 '16 at 10:43

Active Jun 01 '16 at 10:50

Viewed 31 times

Reading a Java project on GitHub, I found a code syntax that I have never seen before and I would some explanation, please. Here is the code:

Book book = new BookBuilder() {
    {
        description("blabla");
        author("blabla");
        title("blabla");
        isbn("123456789");
        category(category);
    }
}.build();

BookBuilder seems to be a standard java class and each of methods called (description, author...) return a BookBuilder object.
My question is, what does the syntax book = new BookBuilder() {{ ... }} means?

edited Jun 01 '16 at 10:50

Andrew Tobilko

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asked Jun 01 '16 at 10:43

gWombat

Is this project supposed to be written in Java 8? – mariosk89 Jun 01 '16 at 10:45
2

Someone seems to have misunderstood the builder pattern.. It's meant to be `new BookBuilder().description("blabla").title("...).build()` without any braces. – zapl Jun 01 '16 at 10:48
1

try to read this http://howtodoinjava.com/core-java/inner-classes/double-brace-initialization-in-java/ – Nogi Jun 01 '16 at 10:50
@marios89 apparently not, the pom is defined with _maven-compiler-plugin_ to 1.7 – gWombat Jun 01 '16 at 10:55
@Nogi, thx for your comment, I will read this article soon. – gWombat Jun 01 '16 at 10:57
@zapl, thx, I will look for more information about this design pattern – gWombat Jun 01 '16 at 10:58

Java instanciation syntax explanation

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