RFR: 8358078: javap crashes with NPE on preview class file [v2]

[Chen Liang]

On Mon, 2 Jun 2025 16:59:34 GMT, Hannes Greule <hgreule at openjdk.org> wrote:

>> This change addresses a NPE in javap when trying to print a class with minorVersion != 0. With this change, we fall back to the methods that don't take a `ClassFileFormatVersion` in such case.
>
> Hannes Greule has updated the pull request incrementally with one additional commit since the last revision:
> 
>   don't return null but latest as fallback

test/langtools/tools/javap/ClassFileVersionTest.java line 85:

> 83:     @ParameterizedTest
> 84:     @MethodSource("classFiles")
> 85:     void test(byte[] classFile, boolean shouldError) throws Throwable {

I recommend adding another String argument indicating the case name - otherwise, if junit fails, the error message reports the argument to string, which is not informative on which class file exactly is being tested.

An alternative approach can be inlining the arguments to `createClassFile` to the case arguments, like

void test(boolean shouldError, int major, int minor, AccessFlag... classFlags)

And junit provides a more useful error message for such arguments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25569#discussion_r2121764380