Java 25 First Impressions

About the most interesting thing in Java 25 is JEP 505 Structured Concurrency. It can clean up a lot of complex code where formerly, one had to jump through hoops to clean up on failure. It looks like it should work very well with the virtual threads that are already introduced. To properly leverage it, it does mean that engineers will need to be more careful around InterruptedException and don't just eat it as was commonplace before. JEP 513 is a 'meh' thing which can help but there was perfectly adequate workarounds using static methods to validate constructor arguments and more. Meanwhile JEP 495 feels kinda pointless.

Random thought: Fixing Java

If Oracle simply changes Java so that null.toString() returns the string "null" instead of throwing a NullPointerException, they will probably solve the majority of mysterious bugs in Java programs.

Random thought: False Hope of Extensibility

Common Java anti-pattern is to name some classes as "DefaultFooClass" when there's actually no way to use any other implementation.

I think it should be called the "False Hope of Extensibility" anti-pattern.

Wooting LEDs from Java

While waiting for things at work, threw together a bit of Java code to tinker with the keyboard LEDs.. Pointless but fun. 😁 Note to self: Should make time to open source it this weekend so that other people can waste their time.
Posted by Antony T Curtis on Wednesday, 20 March 2019

https://github.com/atcurtis/wooting-java
https://www.instagram.com/explore/tags/wooting/
https://www.instagram.com/wootingkb/?hl=en

Java Rock Stars

Opinion:

The rock stars of the Java world never stay on a project long enough, departing immediately when it starts to need cleanup. That way, they're getting the accolades for their achievements and of the people left behind, managers think "these guys are so much less productive than the rock star; we were lucky to have the rock star to get the project started."

Discuss.

Java 8 Streams

This code is certainly more terse from using Java 8 streams but is it more readable than it would be otherwise?

public synchronized void unregister(AsciiString uri, ChannelHandler handler) {
  Optional
      .ofNullable(_handlerMap.get(uri))
      .flatMap(l -> Optional.ofNullable(
          l.stream().filter(p -> p.second == handler)
           .filter(l::remove).findAny().isPresent() ? l : null))
      .filter(List::isEmpty)
      .ifPresent(l -> _handlerMap.remove(uri, l));}

Mucking around with ZooKeeper and Netty 4

ZooKeeper using Netty4 with a common netty worker pool...
Would be trivial to switch it to use the Netty 4 epoll implementation.

Now... To continue what I started hacking on ...

0 [main] INFO org.apache.zookeeper.server.ZooKeeperServer  - Server environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT

...

39 [main] INFO org.apache.zookeeper.server.ZooKeeperServer  - Created server with tickTime 3000 minSessionTimeout 6000 maxSessionTimeout 60000 datadir /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T/org.xiphis.zookeeper.TestZookeeper/zksnap/version-2 snapdir /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T/org.xiphis.zookeeper.TestZookeeper/zklog/version-2

54 [main] DEBUG io.netty.util.internal.logging.InternalLoggerFactory  - Using SLF4J as the default logging framework

60 [main] DEBUG io.netty.util.internal.PlatformDependent0  - java.nio.Buffer.address: available

61 [main] DEBUG io.netty.util.internal.PlatformDependent0  - sun.misc.Unsafe.theUnsafe: available

61 [main] DEBUG io.netty.util.internal.PlatformDependent0  - sun.misc.Unsafe.copyMemory: available

62 [main] DEBUG io.netty.util.internal.PlatformDependent0  - java.nio.Bits.unaligned: true

64 [main] DEBUG io.netty.util.internal.PlatformDependent  - Java version: 8

65 [main] DEBUG io.netty.util.internal.PlatformDependent  - -Dio.netty.noUnsafe: false

65 [main] DEBUG io.netty.util.internal.PlatformDependent  - sun.misc.Unsafe: available

66 [main] DEBUG io.netty.util.internal.PlatformDependent  - -Dio.netty.noJavassist: false

68 [main] DEBUG io.netty.util.internal.PlatformDependent  - Javassist: unavailable

68 [main] DEBUG io.netty.util.internal.PlatformDependent  - You don't have Javassist in your class path or you don't have enough permission to load dynamically generated classes.  Please check the configuration for better performance.

69 [main] DEBUG io.netty.util.internal.PlatformDependent  - -Dio.netty.tmpdir: /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T (java.io.tmpdir)

69 [main] DEBUG io.netty.util.internal.PlatformDependent  - -Dio.netty.bitMode: 64 (sun.arch.data.model)

69 [main] DEBUG io.netty.util.internal.PlatformDependent  - -Dio.netty.noPreferDirect: false

111 [main] DEBUG io.netty.channel.MultithreadEventLoopGroup  - -Dio.netty.eventLoopThreads: 8

172 [main] DEBUG io.netty.channel.nio.NioEventLoop  - -Dio.netty.noKeySetOptimization: false

172 [main] DEBUG io.netty.channel.nio.NioEventLoop  - -Dio.netty.selectorAutoRebuildThreshold: 512

208 [main] INFO org.apache.zookeeper.server.Netty4ServerCnxnFactory  - binding to port 0.0.0.0/0.0.0.0:62326

236 [main] DEBUG io.netty.util.internal.ThreadLocalRandom  - -Dio.netty.initialSeedUniquifier: 0x1216b72d21d3cb0f (took 13 ms)

278 [main] DEBUG io.netty.buffer.ByteBufUtil  - -Dio.netty.allocator.type: unpooled

278 [main] DEBUG io.netty.buffer.ByteBufUtil  - -Dio.netty.threadLocalDirectBufferSize: 65536

282 [main] DEBUG io.netty.util.NetUtil  - Loopback interface: lo0 (lo0, 0:0:0:0:0:0:0:1)

282 [main] DEBUG io.netty.util.NetUtil  - /proc/sys/net/core/somaxconn: 128 (non-existent)

Some project foundation classes for Java.

Have been organising and repackaging some of my source code for release as free open source code. The flavour du jour is Java and these are just a few foundation classes which will be built upon in further packages, hopefully released soon (time permitting). #OpenSource #BSD #Java https://github.com/xiphis/xiphis-utils

I don't care for Gradle.

I could vote for GRADLE-2496 but to be honest, I don't like Gradle enough to create an account just to vote for this issue. Given that the bug was first reported in 2012, few others care enough, too.

10 second thoughts: Gradle

In my opinion, Gradle is a bad idea, implemented poorly. It should never take dozens of gigabytes of RAM and many tens of minutes, just to load its config files and determine that the command asked was mistyped.