Added Lck-File that is correctly deleted on JVM-Exit.

src/main/java/org/sqlite/SQLiteJDBCLoader.java

@@ -29,6 +29,7 @@
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
+import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
@@ -55,19 +56,55 @@
 public class SQLiteJDBCLoader {
 
     private static boolean extracted = false;
+    private static String searchPattern = "sqlite-" + getVersion();
 
     /**
      * Loads SQLite native JDBC library.
      *
-     * @return True if SQLite native library is successfully loaded; false otherwise.
+     * @return True if SQLite native library is successfully loaded; false
+     *         otherwise.
      */
     public static boolean initialize() throws Exception {
+        // only cleanup before first extract
+        if(!extracted) {
+            cleanup();
+        }
         loadSQLiteNativeLibrary();
         return extracted;
     }
 
     /**
-     * @return True if the SQLite JDBC driver is set to pure Java mode; false otherwise.
+     * Deleted old native libraries e.g. on Windows the DLL file is not removed
+     * on VM-Exit (bug #80)
+     */
+    static void cleanup() {
+        String tempFolder = new File(System.getProperty("java.io.tmpdir")).getAbsolutePath();
+        File dir = new File(tempFolder);
+        File[] files = dir.listFiles(new FilenameFilter() {
+            public boolean accept(File dir, String name) {
+                return name.startsWith(searchPattern);
+            }
+        });
+        if(files != null) {
+            for (File tempFile : files) {
+                if(tempFile.getName().indexOf(".lck") > 0) {
+                    continue;
+                }
+                File lckFile = new File(tempFile.getName() + ".lck");
+                if(!lckFile.exists()) {
+                    try {
+                        tempFile.delete();
+                    } catch (SecurityException e) {
+                        System.err.println("Fail deleting old native lib" + e.getMessage());
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * @return True if the SQLite JDBC driver is set to pure Java mode; false
+     *         otherwise.
      * @deprecated Pure Java no longer supported
      */
     static boolean getPureJavaFlag() {
@@ -157,7 +194,11 @@ private static boolean extractAndLoadLibraryFile(String libFolderForCurrentOS, S
         // when multiple JVMs with different architectures running at the same time
         String uuid = UUID.randomUUID().toString();
         String extractedLibFileName = String.format("sqlite-%s-%s-%s", getVersion(), uuid, libraryFileName);
+		String extractedLckFileName = extractedLibFileName + ".lck";
+
         File extractedLibFile = new File(targetFolder, extractedLibFileName);
+		File extractedLckFile = new File(targetFolder, extractedLckFileName);
+
 
         try {
             // Extract a native library file into the target directory
@@ -170,9 +211,14 @@ private static boolean extractAndLoadLibraryFile(String libFolderForCurrentOS, S
                     writer.write(buffer, 0, bytesRead);
                 }
             } finally {
+				if (!extractedLckFile.exists()) {
+					new FileOutputStream(extractedLckFile).close();
+				}
                 // Delete the extracted lib file on JVM exit.
                 extractedLibFile.deleteOnExit();
-
+				extractedLckFile.deleteOnExit();
+
+
                 if(writer != null) {
                     writer.close();
                 }