public static void main(String[] args){
    int maxNumber = 0;
    int secondMaxNumber = 0;
    if(args.length == 0){
      System.err.println("Number array is empty");
      return;
    }
    for(int i=0; i < args.length; i++){
      int currNumber = Integer.parseInt(args[i]);
      if(maxNumber < currNumber){
        secondMaxNumber = maxNumber;
        maxNumber = currNumber;
      }else if(secondMaxNumber < currNumber){
        secondMaxNumber = currNumber;
      }
    }
    System.err.println("Max. number is "+maxNumber);
    System.err.println("Second Max. is "+secondMaxNumber);
  }
}

public class SecondMaximumNumber{
  public static void main(String[] args){
    int maxNumber = 0;
    int secondMaxNumber = 0;
    if(args.length == 0){
      System.err.println("Number array is empty");
      return;
    }
    for(int i=0; i < args.length; i++){
      int currNumber = Integer.parseInt(args[i]);
      if(maxNumber < currNumber){
        secondMaxNumber = maxNumber;
        maxNumber = currNumber;
      }else if(secondMaxNumber < currNumber){
        secondMaxNumber = currNumber;
      }
    }
    System.err.println("Max. number is "+maxNumber);
    System.err.println("Second Max. number is
"+secondMaxNumber);
  }
}

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;


public class SecondMax {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		int[] numbers = {9,4,8,0,0,5,9,1,4,2};
		Set arrSet = new HashSet();
		for (int i=0;i<numbers.length;i++) {
			arrSet.add(numbers[i]);
		}
		ArrayList s = new ArrayList(arrSet);
		Collections.sort(s);

		System.out.println("Second element : " + 
s.get(s.size()-2));
	}
}

Himesh Mistry -best solution