refactor(java): modularize Java detection and management system

- Split monolithic java.rs (1089 lines) into focused modules
  - detection: Java installation discovery
  - validation: Version validation and requirements checking
  - priority: Installation selection priority logic
  - provider: Java download provider trait
  - providers: Provider implementations (Adoptium)
  - persistence: Cache and catalog management
- Add java_path_override field to Instance struct for per-instance Java configuration
- Export JavaInstallation at core module level

This refactoring improves maintainability and prepares for multi-vendor Java provider support.

Reviewed-by: Claude Sonnet 4.5

1 files changed, 82 insertions, 0 deletions

diff --git a/src-tauri/src/core/java/persistence.rs b/src-tauri/src/core/java/persistence.rs
new file mode 100644
index 0000000..0932f2e
--- /dev/null
+++ b/src-tauri/src/core/java/persistence.rs
@@ -0,0 +1,82 @@
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+use tauri::{AppHandle, Manager};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct JavaConfig {
+    pub user_defined_paths: Vec<String>,
+    pub preferred_java_path: Option<String>,
+    pub last_detection_time: u64,
+}
+
+impl Default for JavaConfig {
+    fn default() -> Self {
+        Self {
+            user_defined_paths: Vec::new(),
+            preferred_java_path: None,
+            last_detection_time: 0,
+        }
+    }
+}
+
+fn get_java_config_path(app_handle: &AppHandle) -> PathBuf {
+    app_handle
+        .path()
+        .app_data_dir()
+        .unwrap()
+        .join("java_config.json")
+}
+
+pub fn load_java_config(app_handle: &AppHandle) -> JavaConfig {
+    let config_path = get_java_config_path(app_handle);
+    if !config_path.exists() {
+        return JavaConfig::default();
+    }
+
+    match std::fs::read_to_string(&config_path) {
+        Ok(content) => serde_json::from_str(&content).unwrap_or_default(),
+        Err(_) => JavaConfig::default(),
+    }
+}
+
+pub fn save_java_config(app_handle: &AppHandle, config: &JavaConfig) -> Result<(), String> {
+    let config_path = get_java_config_path(app_handle);
+    let content = serde_json::to_string_pretty(config).map_err(|e| e.to_string())?;
+    std::fs::create_dir_all(config_path.parent().unwrap()).map_err(|e| e.to_string())?;
+    std::fs::write(&config_path, content).map_err(|e| e.to_string())?;
+    Ok(())
+}
+
+pub fn add_user_defined_path(app_handle: &AppHandle, path: String) -> Result<(), String> {
+    let mut config = load_java_config(app_handle);
+    if !config.user_defined_paths.contains(&path) {
+        config.user_defined_paths.push(path);
+    }
+    save_java_config(app_handle, &config)
+}
+
+pub fn remove_user_defined_path(app_handle: &AppHandle, path: &str) -> Result<(), String> {
+    let mut config = load_java_config(app_handle);
+    config.user_defined_paths.retain(|p| p != path);
+    save_java_config(app_handle, &config)
+}
+
+pub fn set_preferred_java_path(app_handle: &AppHandle, path: Option<String>) -> Result<(), String> {
+    let mut config = load_java_config(app_handle);
+    config.preferred_java_path = path;
+    save_java_config(app_handle, &config)
+}
+
+pub fn get_preferred_java_path(app_handle: &AppHandle) -> Option<String> {
+    let config = load_java_config(app_handle);
+    config.preferred_java_path
+}
+
+pub fn update_last_detection_time(app_handle: &AppHandle) -> Result<(), String> {
+    let mut config = load_java_config(app_handle);
+    config.last_detection_time = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap()
+        .as_secs();
+    save_java_config(app_handle, &config)
+}