Java reference.

byte    - 8bit,  1byte,  signed, default: 0
short   - 16bit, 2bytes, signed, default: 0
int     - 32bit, 4bytes, signed, default: 0
long    - 64bit, 8bytes, signed, default: OL
float   - 32bit, 4bytes, default: 0.0f
double  - 64bit, 8bytes, default: 0.0d
boolean - true/false, default: false
char    - 16bit, 2bytes, unicode utf-16, default: '\u0000'
String  - default: null

byte arr[] = new byte[34];
byte arr2[] = new byte[i*2];
System.arraycopy(src, srcOff, dst, dstOff, count)

import java.io.DataInput;
import java.io.FileInputStream;
import java.io.DataInputStream;
import java.io.RandomAccessFile;
DataInputStream di = new DataInputStream(new FileInputStream("c:\\foo.txt");
byte data[] = new byte[64];
di.read(data, 0, 12); // read 12 bytes at offset 0 in data
di.readByte(), .readShort(), readInt() etc.

import java.io.File
File f = new File("c:\\foo.txt");
long size = f.length();