What exactly is ".class" in Java Source Code

Question

I was surfing in SO & I found syntax in Java as below:

String.class.getDeclaredField("value");

I could not understand how it works

Example:

In System.out.println(); out is static variable in System class of PrintWriter

Can any one explain what String.class.getDeclaredField("value"); and it's returning object of Field class means?

I just looked & I couldn't find class property(field) in String class.

What is it actually doing?

Thanks in advance.

Read about java reflection api. – Deepak Jan 29 '14 at 11:03 — Deepak, Jan 29 '14 at 11:03
Please learn what is Class class and Reflection in Java – Keerthivasan Jan 29 '14 at 11:04 — Keerthivasan, Jan 29 '14 at 11:04

score 1 · Accepted Answer · edited May 23 '17 at 12:21

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String.class is a literal that represents the String class which is of type Class<String>. getDeclaredField() is a method defined on the class Class.

see also: What is a class literal in Java?

The literals are defined in the Java Language Specification 15.8.2

edited May 23 '17 at 12:21

Community

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answered Jan 29 '14 at 11:03

Jens Schauder

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but i didnt found in String class where should i look for it? – Jan 29 '14 at 11:04
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It's not a method or field it is part of the class literal syntax – Jens Schauder Jan 29 '14 at 11:06
where this all literal defined? where can i found it? in oracle's site sorry because i am asking out of topic(just near to it?) – Jan 29 '14 at 11:09
@PulahNandha I added a link to the answer – Jens Schauder Jan 29 '14 at 11:21

score 0 · Answer 2 · edited Jan 29 '14 at 11:04

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Look up Java Reflection API and Class.getDeclaredField().

edited Jan 29 '14 at 11:04

Keerthivasan

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answered Jan 29 '14 at 11:03

keshlam

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Thanks for the cosmetic cleanup, Octopus. I've been up all night, so was a bit more terse than optimal. – keshlam Jan 29 '14 at 11:07

What exactly is ".class" in Java Source Code

2 Answers2