Let us no longer create java files

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>
Co-authored-by: Álvaro Brey <alvaro.brey@nextcloud.com>
Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

.github/workflows/detectNewJavaFiles.yml

@@ -0,0 +1,15 @@
+name: "Detect new java files"
+
+on:
+    pull_request:
+        branches: [ master, stable-* ]
+
+jobs:
+    detectNewJavaFiles:
+        runs-on: ubuntu-latest
+
+        steps:
+               - uses: trilom/file-changes-action@v1.2.3
+               - uses: actions/checkout@v2
+               - name: Detect new java files
+                 run: scripts/analysis/detectNewJavaFiles.sh

scripts/analysis/detectNewJavaFiles.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+count=$(grep \.java\" -c "$HOME"/files_added.json)
+
+if [ "$count" -eq 0 ] ; then
+    exit 0
+else
+    echo "New Java files detected! Please use Kotlin for new files. Number of new Java files: $count"
+    exit 1
+fi
+