refactor(java): improve error handling and logging

- Extract JavaError to dedicated error.rs module
- Add serde defaults for JavaInstallation optional fields
- Replace unwrap() with proper error propagation
- Add detailed logging for Java resolution priority chain
- Improve error mapping in validation (NotFound vs VerificationFailed)

Reviewed-by: Claude Sonnet 4.5

1 files changed, 6 insertions, 2 deletions

diff --git a/src-tauri/src/core/java/providers/adoptium.rs b/src-tauri/src/core/java/providers/adoptium.rs
index 4b06721..40e1757 100644
--- a/src-tauri/src/core/java/providers/adoptium.rs
+++ b/src-tauri/src/core/java/providers/adoptium.rs
@@ -1,5 +1,6 @@
+use crate::core::java::error::JavaError;
 use crate::core::java::provider::JavaProvider;
-use crate::core::java::{ImageType, JavaCatalog, JavaDownloadInfo, JavaError, JavaReleaseInfo};
+use crate::core::java::{ImageType, JavaCatalog, JavaDownloadInfo, JavaReleaseInfo};
 use serde::Deserialize;
 use tauri::AppHandle;
 
@@ -183,7 +184,10 @@ impl JavaProvider for AdoptiumProvider {
                     // Task completed but returned None, should not happen in current implementation
                 }
                 Err(e) => {
-                    eprintln!("AdoptiumProvider::fetch_catalog task join error: {:?}", e);
+                    return Err(JavaError::NetworkError(format!(
+                        "Failed to join Adoptium catalog fetch task: {}",
+                        e
+                    )));
                 }
             }
         }