Size of .java file affects compiling.

[khushal malik]

Hi,

I have a .java file whose size is more than 1 GB. Please dont curse me for this as this file is automatically generated by the existing system based on some inputs.

As of now this 1 GB java file is giving errors while compiling. It is not able to compile.

I want to ask does java has such restrictions. Is there a way to compile such file. Other way around is change the code which generates 1GB file.

If you guys have anything related to this please let me know.

regards
khushal

[Jim Yingst]

Offhand I don't remember what if any intrinsic limits there may be in the process. But I'm not surprised that a 1 GB file causes problems. Perhaps you could tell us what is the text of the first few compile errors you get? That may well give important clues as to what, exactly, the problem is.

[Peter Chase]

You can have problems with the JVM that runs javac running out of heap. You can fix these by passing arguments to that JVM using the -J option of javac.

For example, -J-Xms48m sets the initial heap to 48 megabytes.

[Jeroen T Wenting]

The compiler will not accept any sourcefile that has more than 64K lines in any single method.
I'm pretty certain there are similar restrictions to the number of methods per class, data members per class, and classes per file.

Any class that big is a monster that needs serious refactoring anyway
Or if it's generated, kill the generator.

[khushal malik]

Thanks for the help. I will get more details on it. Killing the generator is a nice idea

[Ernest Friedman-Hill]

Originally posted by Jeroen T Wenting:
The compiler will not accept any sourcefile that has more than 64K lines in any single method.

Another limit is 64k bytes of emitted code in a method; sometimes less, as a jump instruction takes a 16-bit signed offset as an argument.

A 1GB emitted file is extremely impressive (or inauspicious, depending on how you look at it.)

[Jim Yingst]

It's definitely something extreme, anyway.

[Paul Clapham]

Originally posted by Jeroen T Wenting:
Any class that big is a monster that needs serious refactoring anyway
Or if it's generated, kill the generator.

Or combine the two ideas and refactor the generator.

[William Brogden]

I am curious where is the bulk in this generated Java source? If it is in String constants perhaps they can be stored elsewhere.

In any case, please let us know the solution you come up with.

Bill

[Tim LeMaster]

I'm with you Bill, I'd love to know how you end up with a 1 GB source file. I can't think of a project that I've worked on that had anywhere near 1 GB of source total.

Just for reference I downloaded "Moby Dick" by Herman Melville from Project Gutenberg, unzipped it is 1.15 MB.

[Murali Mohan]

Hi all,
I faced a similar problem in my project. We use one propertory IDE for development which generates the java code. I found two generated files of size 5 MB. And these files failed to compile because of the large size of methods. Then I manually edited the file and replaced the large methods with a set of small methods and written some logic to integrate these small methods. So that from out side it appeared the same but internally it calls these small methods.