A Samsung handset with the model number SC-02F has recently visited the FCC, headed specifically to Japanese carrier NTT DoCoMo. While the FCC filing doesn't mention a name, multiple content partners list the SC-02F as the Galaxy J, and it seems to be a variant of the Galaxy S4 with the Snapdragon 800 for the Japanese market. An official announcement is expected for sometime in October.
Provided it does turn out to be a Galaxy S4 variant, it will likely sport the same specs as the standard Samsung flagship, including a 5-inch 1080p Super AMOLED screen, 2GB of RAM, 13-megapixel camera, Wi-Fi, HSPA, LTE, Bluetooth, and NFC connectivity, IR blaster, a 2,600mAh battery, and Android 4.2.2 Jelly Bean (Android 4.3 is possible as well, given its launch will be around or after Samsung updates the Galaxy S4 to the latest version of Android).