Solution for print all values at a specific depth in BT, you can see sample BT visualisation here http://www.geeksforgeeks.org/sum-numbers-formed-root-leaf-paths/

PrintLevel.java

public class PrintLevel {

    static PrintLevel ts = new PrintLevel();
	
    public static void main(String[] args) {
	Node l122 = ts.new Node(null, null, 4);
    	Node l121 = ts.new Node(null, null, 7);
    	Node r12 = ts.new Node(null, null, 4);
    	Node l12 = ts.new Node(l122, l121, 5);
    	Node l11 = ts.new Node(null, null, 2);
    	Node r1 = ts.new Node(r12, null, 5);
    	Node l1 = ts.new Node(l12, l11, 3);
    	Node root = ts.new Node(r1, l1, 6);
    	printLevel(root, 1);
    }
	
    public static void printLevel(Node node, int level) {
        dfsLevel(node, level, 1);
    }
    
    public static void dfsLevel(Node node, int level, int curLevel) {
        if(node == null) return;
        if(level == curLevel) {
            System.out.print(node.value + " ");
            return;
        }
        curLevel++;
        dfsLevel(node.left, level, curLevel);
        dfsLevel(node.right, level, curLevel);
    }
    
    class Node {
    	
    	Node right;
        Node left;
        int value;
        
    	public Node(Node right, Node left, int value) {
    		this.right = right;
    		this.left = left;
    		this.value = value;
    	}
        
    }
}