Hardened argument validation

pom.xml

@@ -50,6 +50,14 @@
             <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
+
+        <!-- AssertJ for testing -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.27.6</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/com/tidesdb/TidesDBIterator.java

@@ -65,8 +65,8 @@ public void seekToLast() throws TidesDBException {
      */
     public void seek(byte[] key) throws TidesDBException {
         checkNotFreed();
-        if (key == null) {
-            throw new IllegalArgumentException("Key cannot be null");
+        if (key == null || key.length == 0) {
+            throw new IllegalArgumentException("Key cannot be null or empty");
         }
         nativeSeek(nativeHandle, key);
     }
@@ -79,8 +79,8 @@ public void seek(byte[] key) throws TidesDBException {
      */
     public void seekForPrev(byte[] key) throws TidesDBException {
         checkNotFreed();
-        if (key == null) {
-            throw new IllegalArgumentException("Key cannot be null");
+        if (key == null || key.length == 0) {
+            throw new IllegalArgumentException("Key cannot be null or empty");
         }
         nativeSeekForPrev(nativeHandle, key);
     }

src/main/java/com/tidesdb/Transaction.java

@@ -51,8 +51,8 @@ public void put(ColumnFamily cf, byte[] key, byte[] value, long ttl) throws Tide
         if (cf == null) {
             throw new IllegalArgumentException("Column family cannot be null");
         }
-        if (key == null) {
-            throw new IllegalArgumentException("Key cannot be null");
+        if (key == null || key.length == 0) {
+            throw new IllegalArgumentException("Key cannot be null or empty");
         }
         if (value == null) {
             throw new IllegalArgumentException("Value cannot be null");
@@ -85,8 +85,8 @@ public byte[] get(ColumnFamily cf, byte[] key) throws TidesDBException {
         if (cf == null) {
             throw new IllegalArgumentException("Column family cannot be null");
         }
-        if (key == null) {
-            throw new IllegalArgumentException("Key cannot be null");
+        if (key == null || key.length == 0) {
+            throw new IllegalArgumentException("Key cannot be null or empty");
         }
         return nativeGet(nativeHandle, cf.getNativeHandle(), key);
     }
@@ -103,7 +103,7 @@ public void delete(ColumnFamily cf, byte[] key) throws TidesDBException {
         if (cf == null) {
             throw new IllegalArgumentException("Column family cannot be null");
         }
-        if (key == null) {
+        if (key == null || key.length == 0) {
             throw new IllegalArgumentException("Key cannot be null");
         }
         nativeDelete(nativeHandle, cf.getNativeHandle(), key);

src/test/java/com/tidesdb/TidesDBTest.java

@@ -443,4 +443,47 @@ void testCustomColumnFamilyConfig() throws TidesDBException {
             assertEquals("custom_cf", cf.getName());
         }
     }
+
+    @Test
+    @Order(13)
+    void testTransactionPutGetDeleteBadKey() throws TidesDBException {
+        Config config = Config.builder(tempDir.resolve("testdb3").toString())
+                .numFlushThreads(2)
+                .numCompactionThreads(2)
+                .logLevel(LogLevel.INFO)
+                .blockCacheSize(64 * 1024 * 1024)
+                .maxOpenSSTables(256)
+                .build();
+
+        try (TidesDB db = TidesDB.open(config)) {
+            ColumnFamilyConfig cfConfig = ColumnFamilyConfig.defaultConfig();
+            db.createColumnFamily("test_cf", cfConfig);
+
+            ColumnFamily cf = db.getColumnFamily("test_cf");
+
+            byte[] key = new byte[0]; // Bad key (empty)
+            byte[] value = "value".getBytes(StandardCharsets.UTF_8);
+
+            assertThrows(IllegalArgumentException.class, () -> {
+                try (Transaction txn = db.beginTransaction()) {
+                    txn.put(cf, key, value);
+                }
+            });
+
+            assertThrows(IllegalArgumentException.class, () -> {
+                try (Transaction txn = db.beginTransaction()) {
+                    byte[] result = txn.get(cf, key);
+                    assertNotNull(result);
+                    assertArrayEquals(value, result);
+                }
+            });
+
+            assertThrows(IllegalArgumentException.class, () -> {
+                try (Transaction txn = db.beginTransaction()) {
+                    txn.delete(cf, key);
+                    txn.commit();
+                }
+            });
+        }
+    }
 }