Is power of two

Determine if a number is power of two.
## First Approach
<pre>
<code>
double x=Math.log(n)/Math.log(2);
return x==(int)x;
</code>
</pre>
Obviously it failed some test cases, double could not contain larger values.
## Second Approach
<pre>
<code>
static boolean isPowerOfTwo(int n) 
{ 
    if(n==0) 
    return false; 
  
return (int)(Math.ceil((Math.log(n) / Math.log(2)))) ==  
       (int)(Math.floor(((Math.log(n) / Math.log(2))))); 
} 
<pre>
<code>
gave error for test case 5837012
<pre>
<code>
class Solution {
    public boolean isPowerOfTwo(int n) {
        if(n==0) return false;
        while(n!=1){
            if(n%2!=0){
              return false;  
            }
            n=n/2;
        }
        
        return true;
    }
}
</pre>
</code>