javac error “code too large”?

Question

I have a unit test where I have statically defined a quite large byte array (over 8000 bytes) as the byte data of a file I don\'t want to read every time I run my unit test.

Answer 1

Methods in Java are restricted to 64k in the byte code. Static initializations are done in a single method (see link)
You may try to load the array data from a file.

Answer 2

You can leverage inner classes as each would have it's own 64KB limit. It may not help you with a single large array as the inner class will be subject to the same static initializer limit as your main class. However, you stated that you managed to solve the issue by moving your array to a separate class, so I suspect that you're loading more than just this single array in your main class.

Instead of:

private static final byte[] FILE_DATA = new byte[] {12,-2,123,...,<LARGE>};

Try:

private static final class FILE_DATA
{
    private static final byte[] VALUES = new byte[] {12,-2,123,...,<LARGE>};
}

Then you can access the values as FILE_DATA.VALUES[i] instead of FILE_DATA[i], but you're subject to a 128KB limit instead of just 64KB.

Answer 3

You can load the byte array from a file in you @BeforeClass static method. This will make sure it's loaded only once for all your unit tests.