Improve Temurin JDK version detection

Enhances the setup_java function to attempt a package purge and reinstall if a Temurin JDK is detected but its version cannot be determined. This helps recover from inconsistent or broken JDK installations.

Author: MickLesk

misc/tools.func

@@ -2784,12 +2784,19 @@ function setup_java() {
     INSTALLED_VERSION=$(dpkg -l 2>/dev/null | awk '/temurin-.*-jdk/{print $2}' | grep -oP 'temurin-\K[0-9]+' | head -n1 || echo "")
   fi
 
-  # Validate INSTALLED_VERSION is not empty if matched
+  # Validate INSTALLED_VERSION is not empty if JDK package found
   local JDK_COUNT=0
   JDK_COUNT=$(dpkg -l 2>/dev/null | grep -c "temurin-.*-jdk" || true)
   if [[ -z "$INSTALLED_VERSION" && "${JDK_COUNT:-0}" -gt 0 ]]; then
-    msg_warn "Found Temurin JDK but cannot determine version"
-    INSTALLED_VERSION="0"
+    msg_warn "Found Temurin JDK but cannot determine version - attempting reinstall"
+    # Try to get actual package name for purge
+    local OLD_PACKAGE
+    OLD_PACKAGE=$(dpkg -l 2>/dev/null | awk '/temurin-.*-jdk/{print $2}' | head -n1 || echo "")
+    if [[ -n "$OLD_PACKAGE" ]]; then
+      msg_info "Removing existing package: $OLD_PACKAGE"
+      $STD apt purge -y "$OLD_PACKAGE" || true
+    fi
+    INSTALLED_VERSION="" # Reset to trigger fresh install
   fi
 
   # Scenario 1: Already at correct version