Find Larget Prime Factor

LargestPrimeFactor.java

public class Test
{
  public static void main(String[] args)
  {
    LargestPrimeFactor myObject = new LargestPrimeFactor();
    
    long largestPrimeFactor = myObject.largestPrimeFactor(600851475143L);
    System.out.println("largest prime Factor: " + largestPrimeFactor);
  }
}

public class LargestPrimeFactor
{
  
  public long largestPrimeFactor(long n){
    long curr = n;
    for (long i=2; i < curr; i++){
      if (curr % i == 0){
        curr = curr/i;
        System.out.println("potential largest prime Factor: " + curr + " divisor: " + i);
        i = 2;
        if (isPrime(curr)){
          return curr;
        }
      }
    }
    return -1;
  }

  public boolean isPrime(long n) {
    //check if n is a multiple of 2
    if (n%2==0) return false;
    //if not, then just check the odds
    for(int i=3;i*i<=n;i+=2) {
      if(n%i==0)
        return false;
    }
    return true;
  }
}

/*output:

potential largest prime Factor: 8462696833 divisor: 71
potential largest prime Factor: 10086647 divisor: 839
potential largest prime Factor: 6857 divisor: 1471
largest prime Factor: 6857

*/



//More optimal solution:

public class PrimeTest
{
  public static void main(String[] args)
  {
    PrintPrimeFactors myObject = new PrintPrimeFactors();
    myObject.primeFactors(600851475143L);
  }
}

public class PrintPrimeFactors
{
  public void primeFactors(long n)
  {
      long largestPrime = 0;
      // Print the number of 2s that divide n
      while (n%2 == 0)
      {
          
          largestPrime = 2;
          System.out.println(String.format("divisable by 2 : %-8d", largestPrime)); 	
          n = n/2;
      }

      // n must be odd at this point.  So we can skip one element (Note i = i +2)
      for (int i = 3; i * i <= n; i = i+2)
      {
          // While i divides n, print i and divide n
          while (n%i == 0)
          {
             largestPrime = i;
             System.out.println(String.format("divisable by: %-8d", largestPrime)); 	
              n = n/i;
          }
      }

      // This condition is to handle the case whien n is a prime number
      // greater than 2
      if (n > 2){
        System.out.println(String.format("n greater than 2 : %-8d", n)); 	
		largestPrime = n;
      }
        
      System.out.println(String.format("Largest Prime: %-8d", largestPrime));
     
  }
}

/*output:

divisable by: 71      
divisable by: 839     
divisable by: 1471    
n greater than 2 : 6857    
Largest Prime: 6857   

*/

public class LargestPrimeFactor { public static void main(String[] args) { System.out.println(largestPrimefactor(10)); } private static long largestPrimefactor(long num) { long n = num; long p = 0; for (int i = 2; i <=n-1; i++) { if(n%i==0 && i>p) { p = i; } else { continue; } } if(p==0) { // This step is for prime numbers which has prime factor equal to itself p = n; } return p; } }