private boolean duplicateFieldDefined(String line) {
		
		String[] splitLine = line.split("(?=[^a-zA-Z0-9])|(?<=[^a-zA-Z0-9])");
		ArrayList<String> test = new ArrayList<String>();
		
		for(String str : splitLine)
			if(Assembler.isAlphaNumeric(str))
				test.add(str);
		
		for (int j=0;j<test.size();j++) {
		    for (int k=j+1;k<test.size();k++) {
		        if (test.get(k).equals(test.get(j))){ 
		            return true;
		        }
		    }
		}
		return false;
	}