jdk7u-jdk VS JDK

Skip lists are relatively simple to make lock-free, while lock-free (even unbalanced) binary search trees are an absolute nightmare.

https://github.com/openjdk-mirror/jdk7u-jdk/blob/master/src/...

Here is the JDK 7 String#hashCode(), which operates on characters: https://github.com/openjdk-mirror/jdk7u-jdk/blob/f4d80957e89....

That's changed in the newer versions, because String has a `byte[]` not a `char[]`, but it was just fine. A hash algorithm can take in bytes, characters, ints, it doesn't matter.

In Java, you don't get access to the bytes that make up a string, to preserve the string's immutability. So for many operations where you might operate on bytes in a lower level language, you end up using characters (unless you're the standard library, and you can finagle access to the bytes), or alternately doing a byte copy of the entire string.

I admit, checksums using characters are a bit weird sounding, but they should also be perfectly well-defined.

"AbstractInterruptibleChannel" seems to be doing this, and the comments/javadocs offer some hint. As to why they're designed this way, that's a good question.

https://github.com/openjdk-mirror/jdk7u-jdk/blob/master/src/...

In Java, you could use BigDecimal. I linked to the source code, because it highlights the amount of complexity you get.

The windows implementation of AWT Desktop just calls the Win32 API ShellExcute function. This then quickly descends into questions such as "what version of windows do you have"; "does it correctly understand the difference between open vs. edit"; what does your registry currently contain"; etc.

ArrayList is a class, it is not an array. It stores two values. An array and its size. You can see this if you read the source code for ArrayList.

The source code for the Java SDK is available on github.

I felt out of the loop, thinking that Zero VM was some kind of new distro for OpenJDK but chasing <https://packages.debian.org/sid/openjdk-22-jre-zero#:~:text=...> to <https://sources.debian.org/src/openjdk-11/11.0.23%2B9-1/debi...> lead me to https://github.com/openjdk/jdk/tree/jdk-22-ga/src/hotspot/cp...

It seems that it's a specific CPU target for the Hotspot JIT for non-mainstream architectures (or for research purposes, as I saw mentioned once)

Completely gutted from the OpenJDK, last I checked. See here for the culprit PR: https://github.com/openjdk/jdk/pull/18688

> Yes, they're changing one aspect of signal handler use to work around this problem. They're not stopping the use of signal handlers in general. Hotspot continues to use signals for efficiency in general. See https://github.com/openjdk/jdk/blob/9059727df135dc90311bd476...

This whole thread is about SIGSEGV, and specifically their SIGSEGV handling. However, catching normal signals is not about efficiency.

Some of their exception handling is still odd: There is no reason for a program that receives SIGILL to ever attempt continuing. But others is fine, like catching SIGFPE to just forward an exception to the calling code.

(Sure, you could construct an argument to say that this is for efficiency if you considered the alternative to be implementing floating point in software so that all exceptions exist in user-space, but hardware floating point is the norm and such alternative would be wholly unreasonable.)

> The wonderful thing about choosing not to care about facts is having whatever opinions you want.

I appreciate the irony of you making such statement, proudly thinking that your opinion equals fact, and therefore any other opinion is not.

This discussion is nothing but subjective opinion vs. subjective opinion. Facts are (hopefully, as I can only speak for myself) inputs to both our opinions, but no opinion about "good" or "bad", "nasty" or not can ever be objective. Objective code quality does not exist.

I remember talking to Brendan about the PreserveFramePointer patch during my first months at Netflix in 2015. As of JDK 21, unfortunately it is no longer a general purpose solution for the JVM, because it prevents a fast path being taken for stack thawing for virtual threads: https://github.com/openjdk/jdk/blob/d32ce65781c1d7815a69ceac...