Using Unsigned Int 32 Bit in Java? [Duplicate]

Possible Duplicate:
Converting 32-bit unsigned integer (big endian) to long and back

I want to translate this expression in Java

char tab[100];
tab[10] = '\xc0';

tab[48] = '\x80';

uint32_t w = 0x67452301;

uint32_t x = 0xefcdab89;

uint32_t y = 0x98badcfe;

uint32_t z = 0x10325476;

a = ((b & c) | (~b & d)) + (*(uint32_t*)(tab+0x00)) + a - 0x28955B88;

a = ((a << 0x07) | (a >> 0x19)) + b;

I'have tried this but...

char[] tab = new char[64];

 tab[10] = (char) 0xc0; 
 tab[48] = (char) 0x80; 

but the value is not the right one, is there another way to assign \0x80 in a char[] ? How can i interprete this kind of cast in java ((uint32_t)) ?

Many thanks !