edited file existence to be more explicit

Author: dhruvarayasam

src/main/java/com/example/core/model/GGUF.java

@@ -1,18 +1,21 @@
 package com.example.core.model;
 
 import com.example.auxiliary.Timer;
+import com.example.core.model.GGUF.GGUFTensorInfo;
 import com.example.core.model.tensor.FloatTensor;
 import com.example.core.model.tensor.GGMLTensorEntry;
 import com.example.core.types.MetadataValueType;
 import com.example.core.types.Pair;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.lang.foreign.Arena;
 import java.lang.foreign.MemorySegment;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.HashMap;
 import java.util.List;
@@ -36,17 +39,19 @@ public final class GGUF {
     private long tensorDataOffset;
 
     public static GGUF loadModel(Path modelPath) throws IOException {
+
+        // file existence check
+        if (!Files.exists(modelPath)) {
+            throw new FileNotFoundException("Model file not found: " + modelPath);
+        }
+
+        // second check to make sure that nothing goes wrong during model loading
         try (FileChannel fileChannel = FileChannel.open(modelPath); var ignored = Timer.log("Parse " + modelPath)) {
             GGUF gguf = new GGUF();
             gguf.loadModelImpl(fileChannel);
             return gguf;
-        } catch {
-
-            IOException e -> {
-                throw new IOException("Failed to load GGUF model from " + modelPath, e);
-            } 
-            
-            catch (Exception e) {
+        } catch (Exception e) {
+             {
                 throw new RuntimeException("Unexpected error while loading GGUF model from " + modelPath, e);
             }