This game is abandonware. The original developer (likely a small mod team) no longer distributes or profits from it. Konami has never issued a takedown for this fan-game, as it does not use official copyrighted code—only thematic inspiration. Downloading it falls into a grey area, but for preservation and personal use, it is widely tolerated within the retro community.
Castlevania 4 Demon " (often known in J2ME circles as Castlevania: Demon Hunter Castlevania Dungeon Castlevania 4 Demon English Version 320x240 Jar Download
While the query specifically refers to a "Castlevania 4 Demon English Version 320x240 Jar," this is not an official Konami release. Instead, it refers to a Chinese mobile (Java/J2ME) bootleg or fan-made port This game is abandonware
To play a .jar file on a modern smartphone or PC, you will need a J2ME emulator: Downloading it falls into a grey area, but
Thus, searching for "Castlevania 4 Demon English Version 320x240 Jar Download" ensures you get the exact build compatible with most QVGA feature phones and emulators set to that resolution.