powersort/README.md

# Bring Powersort to Java

## Gradle

### Setup

**Commandline**

Check which Java toolchains can be found by Gradle:

```shell
./gradlew javaToolchains
```

- `shell.nix` -> broken (as well for `gradle javaToolchains`
- `shell1.nix` -> works 🥳
- `shell2.nix` -> broken (as well for `gradle javaToolchains`)
- `shell3.nix` -> works 🥳
- `shell4.nix` -> works 🥳

This should include version >= 17, e.g.:

```
 + N/A JDK 23-ga
     | Location:           /nix/store/48290hnlb13xmwjw9y16a1s785993bv7-openjdk-23-ga/lib/openjdk
     | Language Version:   23
     | Vendor:             N/A
     | Architecture:       amd64
     | Is JDK:             true
     | Detected by:        Current JVM
```

**IntelliJ**

Open issue: gradle's toolchain support does not work with IntelliJ

- `shell.nix`
  - Solution from 2022 did no longer work: https://github.com/NixOS/nixpkgs/issues/207153#issue-1506967648
- `shell1.nix`
  - Instead, we found this: https://discourse.nixos.org/t/overriding-the-jdk-for-gradle-in-a-nix-flake/36541/2
- `shell2.nix`
  - Another approach - which did no longer work! https://github.com/utybo/Tegral/blob/main/shell.nix
- `shell3.nix`
  - This works with JDK 21 🥳
  - STRG ALT SHIFT s -> SDK -> add JDK ->
    - home path: /usr/lib/openjdk
    - name: usr-lib-jdk
  - STRG ALT s -> build tools -> gradle ->
    - local installation: /usr/lib/gradle
    - Gradle JVM: usr-lib-jdk
- `shell4.nix`
  - This works with JDK23 🚀

### Tasks

List all Gradle tasks which can be run:

```shell
./gradlew tasks
```

This can also be done graphically in IntelliJ:

![intellij-gradle.png](intellij-gradle.png)

### Test Cases

Run the task "test":

```shell
./gradlew test
```

## TimSort

Imported from
- src/java.base/share/classes/java/util/TimSort.java
- src/java.base/share/classes/java/util/ComparableTimSort.java