CodeReview

 
 public   class   CodeReview
{
 /// <summary>
 /// This method returns integer parsed from the source.  /// If parsing fails it should return zero.
 /// </summary>
 /// <param name="o">Object with data to parse.</param>  /// <returns>Parsed value</returns>
 public   int   Parse ( object  o)
{
 return   int . Parse ( o . ToString ()); }
 /// <summary>
 /// This method returns concatenated string from the array of the strings.
 /// </summary>
 /// <param name="lines">Array of strings with lines.</param>  /// <returns>Concatenated string.</returns>
 public   string   Concat ( string []  lines)
{
 string  result;
 for ( int  i  =   0 ;  i  <  lines . Length ;  i ++)
{
result  +=  lines [ i ];
}
 return  result; 
}
}

/**
 * @author FatNinja
 */
public class Runner {
 
    public static void main(String[] args) {
        
        // demo parse 1
        System.out.println(Integer.valueOf("42"));
        
        // demo parse 2 
        try {
            System.out.println(Integer.valueOf(" 42"));
        } catch (NumberFormatException ex) {
            System.out.println("Parse error: " + ex.getMessage());
        }
        
        // demo concat
        String[] lines = { "1", "st ", "2", "nd ", "3", "rd"};
        System.out.println(new Common().concat(lines));
        
    }
}
 
class Common {
    
    // TODO method Parse doesn't make sense
    // use Integer.valueOf()
    
    /**
     * This method returns concatenated string from the array of the strings.
     * @param lines array of strings with lines.
     * @return concatenated string.
     */
    public String concat(String[] lines) {
        StringBuilder builder = new StringBuilder();
        for (String current : lines) {
            builder.append(current);
        }
        return builder.toString();
    } 
}