A BrainF**k intepreter in Java.

Juck.java

import java.util.Stack;
import java.util.Scanner;
import java.util.HashMap;
import java.io.FileReader;
import java.util.ArrayList;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileNotFoundException;

class Juck {
	
	static int[] array;
	static int size = 32;
	static int pointer = 0;
	static String code = "";
	static String type = "int";
	static BufferedReader source;
	static boolean checkBoundary = false;
	static HashMap<Integer, Integer> brackets;
	
	static final String DOC_STRING = "Usage: java Juck [-options] filename\n\nwhere options include:\n\t-s power\t\tsize of the array is given by pow(2, power + 5). Default value is 0. Can range from 0 to 5, inclusive.\n\t-t type\t\t\tthe type of the array, either integer (default) or character. type should be int for integer or char for character.\n\t-x\t\t\tChecks array boundary.\n\t-h\t\t\tPrints this documentation and exits.";
	
	public static void printHelp() {
		
		System.out.println(Juck.DOC_STRING);
		System.exit(-1);
	}
	
	public static void parseOptions(String[] args) {
		
		int i;
		
		if(args.length == 0)
			Juck.printHelp();
		
		for(i = 0; i < args.length; i++) {
			if(args[i].equals("-h"))
				Juck.printHelp();
			
			else if(args[i].equals("-s")) {
				try {
					Juck.size = 1 << (5 + Integer.parseInt(args[++i]));
					
					if(Juck.size < 32 || Juck.size > 1024)
						Juck.printHelp();
				}
				
				catch(Exception e) {
					Juck.printHelp();
				}
			}
			
			else if(args[i].equals("-t")) {
				Juck.type = args[++i];
				
				if(!(Juck.type.equals("int") || Juck.type.equals("char")))
					Juck.printHelp();
			}
			
			else if(args[i].equals("-x"))
				checkBoundary = true;
			
			else if(i != args.length - 1) {
				System.out.println("Invalid operand: " + args[i]);
				Juck.printHelp();
			}
		}
		
		try {
			Juck.source = new BufferedReader(new FileReader(args[--i]));
		}
		
		catch(FileNotFoundException e) {
			System.out.println("Cannot find the given file.");
			System.exit(-2);
		}
		
		catch(IOException e) {
			System.out.println("Cannot read the given file.");
			System.exit(-3);
		}
		
		catch(Exception e) {
			Juck.printHelp();
		}
	}
	
	public static void readSource() {
		
		int c;
		
		try {
			while((c = source.read()) != -1)
				if((c > 42 && c < 47) || c == 60 || c == 62 || c == 91 || c ==93)
					Juck.code += (char) c;
		}
		
		catch(IOException e) {
			System.out.println("Cannnot read the given file.");
			System.exit(-4);
		}
	}
	
	public static void grabBrackets() {
		
		int j;
		Stack<Integer> stack = new Stack<Integer>();
		Juck.brackets = new HashMap<Integer, Integer>();
		
		for(int i = 0; i < Juck.code.length(); i++) {
			if(Juck.code.charAt(i) == '[')
				stack.push(i);
			
			else if(Juck.code.charAt(i) == ']') {
				if(stack.empty()) {
					System.out.println("Unexpected ']'");
					System.exit(-5);
				}
				
				j = stack.pop();
				Juck.brackets.put(i, j);
				Juck.brackets.put(j, i);
			}
		}
		
		if(!stack.empty()) {
			System.out.println("Cannot find matching ']'");
			System.exit(-5);
		}
	}
	
	public static void run() {
		
		int i = 0;
		char current;
		int eol = Juck.code.length();
		Scanner terminal = new Scanner(System.in);
		
		Juck.array = new int[Juck.size];
		
		while(i != eol) {
			current = Juck.code.charAt(i);
			
			if(current == '>') {
				pointer++;
				
				if(pointer == Juck.size) {
					if(checkBoundary) {
						System.out.println("Array Index Out of Bounds.");
						System.exit(-6);
					}
					
					pointer = 0;
				}
			}
			
			else if(current == '<') {
				pointer--;
				
				if(pointer == -1) {
					if(checkBoundary) {
						System.out.println("Array Index Out of Bounds.");
						System.exit(-6);
					}
					
					pointer += Juck.size;
				}
			}
			
			else if(current == '+')
				Juck.array[pointer]++;
			
			else if(current == '-')
				Juck.array[pointer]--;
			
			else if(current == '.') {
				if(Juck.type.equals("char"))
					System.out.print((char) Juck.array[pointer]);
				
				else
					System.out.println(Juck.array[pointer]);
			}
			
			else if(current == ',') {
				System.out.print(">");
				
				try {
					if(Juck.type.equals("char"))
						Juck.array[pointer] = (char) System.in.read();
					
					else
						Juck.array[pointer] = terminal.nextInt();
				}
				
				catch(Exception e) {
					System.out.println("Invalid input.");
					System.exit(-7);
				}
			}
			
			else if(current == '[' && Juck.array[pointer] == 0)
				i = Juck.brackets.get(i);
			
			else if(current == ']' && Juck.array[pointer] != 0)
				i = Juck.brackets.get(i);
			
			i++;
		}
	}
	
	public static void main(String args[]) {
		
		Juck.parseOptions(args);
		Juck.readSource();
		Juck.grabBrackets();
		Juck.run();
	}
	
}