Stack Implementation using Queue - Java Code

Get Implementation below:

     
import java.util.ArrayDeque;
import java.util.Queue;

public class StackUsingQueue {
 Queue q1=new ArrayDeque<>();
 Queue q2=new ArrayDeque<>();
 
 public void push(Integer item) {
  if(!q1.isEmpty())
   q1.add(item);
  else
   q2.add(item);
  System.out.println("PUSH "+item+": Q1: "+q1+"   Q2"+q2);
 }
 public void pop() {
  Integer item ;
  if(!q1.isEmpty()) {
   transfer(q1, q2);
   item = q1.poll();
  }else {
   transfer(q2, q1);
   item = q2.poll();
  }
  System.out.println("POP : Q1: "+q1+"   Q2"+q2+"  -  Poped Item:"+item);
 }
 
 private void transfer(Queue q1, Queue q2) {
  Integer size = q1.size();
  for(int i=0; i< size - 1; i++)
   q2.add(q1.poll());
 }
 public static void main(String[] args) {
  StackUsingQueue stack = new StackUsingQueue();
  stack.push(1);
  stack.push(2);
  stack.pop();
  stack.push(3);
  stack.push(4);
  stack.pop();
  stack.pop();
 }
  }

Result

PUSH 1: Q1: []   Q2[1]
PUSH 2: Q1: []   Q2[1, 2]
POP : Q1: [1]   Q2[]  -  Poped Item:2
PUSH 3: Q1: [1, 3]   Q2[]
PUSH 4: Q1: [1, 3, 4]   Q2[]
POP : Q1: []   Q2[1, 3]  -  Poped Item:4
POP : Q1: [1]   Q2[]  -  Poped Item:3

Why Crontab Scripts are not running ?

Sometimes The bash scripts runs good at the Terminal, But doesnt execute while running from cromtab.

I faced same issue with multiple commands chained in a crontab,

Solution: Issue behind the command is, while executing crontab everu command should have have the complete path.

You can find the command path as follows:
for example xargs

• Execute "which xargs" which will give the complete path as /usr/bin/xargs

So I formated my cronjob as follows:

• Before Path : 44 * * * * echo $(service MyService status | xargs -n 1 lsof -p | wc -l) 
• After Path : 44 * * * * echo $(/sbin/service MyService status | /usr/bin/xargs -n 1 /usr/bin/lsof -p | /usr/bin/wc -l) 

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