Is there something like C's struct in Java?

Question

struct is necessary when you try to parse some file format like ELF, etc...

Or can Java be used to parse ELF/binary format directly in the first place?

Further reading on SO (with many pointers to other Q/A around "struct" in Java) : http://stackoverflow.com/questions/36701/struct-like-objects-in-java — Andreas Dolk, Aug 11 '11 at 11:40
*"struct is necessary when ..."* Necessary is too strong. Convenient, and even then assuming that you have solved issues surrounding endianess, packing, and the sizes of built-in types. — dmckee --- ex-moderator kitten, Aug 30 '11 at 14:50

score 2 · Answer 1 · answered Aug 11 '11 at 11:38

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If you need a struct for grouping different data of the same type, Java has a class, and a class is better in logically grouping data than a struct because it includes operations on the data as well.

If you want to format ELF, then you may have to look at the "The ELF Parser" section in http://www.icsa.inf.ed.ac.uk/research/groups/hase/manuals/design/javahase.html. See also LibElf and GElf - A Library to Manipulate ELf Files (an old article)

answered Aug 11 '11 at 11:38

Nivas

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In C, you can read a binary blob directly into a struct. This is the reason the OP asks for a struct, to easily parse a series of bytes into an ELF structure. I assume the OP knows about Java classes, but in Java it is not as easy to deserialize a series of bytes into a class. – Sjoerd Aug 11 '11 at 12:05
@Sjoerd, this was not clear in the question. But yes, this very well could be his intention, especially considering the answer he has accepted... – Nivas Aug 11 '11 at 12:51

SimonC · Answer 2 · 2011-08-11T11:41:03.477

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There's ByteBuffer.

Edit

This is just to answer how you might parse the ELF format, which seemed to be what the OP was actually asking for.

For example (I assume this is the same format, apologies if it's a completely different ELF format, either way, it shows the same process):

http://jumdbrowser.googlecode.com/svn-history/r3/trunk/UmdBrowser/src/jpcsp/format/Elf32.java

edited Aug 11 '11 at 11:41

answered Aug 11 '11 at 11:33

SimonC

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How does ByteBuffer relate to C++ Struts? – Buhake Sindi Aug 11 '11 at 11:37

score 1 · Accepted Answer · answered Aug 11 '11 at 11:41

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Unfortunatly there is no decent support to read binary structured data in java.

This example reads image header into a byte array and assembles the required information.

answered Aug 11 '11 at 11:41

stacker

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Manuel Selva · Answer 4 · 2011-08-11T11:46:14.877

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Edit: answer to the first question

Java classes

edited Aug 11 '11 at 11:46

answered Aug 11 '11 at 11:35

Manuel Selva

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Bit of a sarcastic response to sensible question (assuming the OP is asking how you would parse a binary format). – SimonC Aug 11 '11 at 11:42
My initial answer to the question was: Java Classes bu SO told me it was too short ... :-( – Manuel Selva Aug 11 '11 at 11:43

Is there something like C's struct in Java?

4 Answers4