How do i get rid of these zeros?

I tried to change a couple of things, but the zeros remained. Any idea how I can get rid of them? Would it have to do with main or maybe with encrypt and decrypt methods?

public static void main(String args[]) {

    Tea t = new Tea(k, p);

    p[0] = 0x01234567;
    p[1] = 0x89abcdef;
    k[0] = 0xa56babcd;
    k[1] = 0xffffffff;
    k[2] = 0xffffffff;
    k[3] = 0xabcdef01;

    System.out.println("Plaintext: " + Integer.toHexString(p[0]) + Integer.toHexString(p[1]));

    System.out.println("Key: " + Integer.toHexString(k[0]) + Integer.toHexString(k[1])
            + Integer.toHexString(k[2]) + Integer.toHexString(k[3]));

    System.out.print("Ciphertext: ");

    int cipher = t.encrypt(p, k);

    System.out.println(Integer.toHexString(cipher));

    System.out.print("Decrypted Plaintext: ");

    int decryptplain = t.decrypt(p, k);

    System.out.println(Integer.toHexString(decryptplain));
}

Output:

Plaintext: 123456789abcdef
Key: a56babcdffffffffffffffffabcdef01
Ciphertext: fe18f8f3fcb8dcd3
0
Decrypted Plaintext: 123456789abcdef
0