How to fix exception in thread main java lang common exceptions

public class Test

public static void main(String[] args)

            Student st = new Student();

            System.out.println("Result: " + st.sayHello());

              class Student

        private String name;

        public String sayHello()

            return "Hello " + name.toUpperCase();

  public void setName(String name)

            this.name = name;

Variable length Argument Lists

public class VarargsTest

 public static void main(String[] args)

       System.out.println(" Sum = " + sum(41, 22, 58));

        static int sum(int... numbers)

            int sum = 0;

            for (int i = 0; i < numbers.length; i++)

                sum += numbers[i];

            return sum;

Static Import

import static java.lang.Integer.*;

import static java.lang.String.format;

           public class StaticImportTest

 public static void main(String[] args)

            int num = parseInt("526");

            Integer.parseInt()

            Integer num2 = valueOf("123");

            Integer.valueOf()

            String.format()

            System.out.println(format("Numbers: %d, %d", num, num2));

            Integer.Max_Value

            System.out.println(" Integer Max value = " + Max_Value);

package testing;
import java.util.Scanner;

public class NoClassDefFoundErrorDueToStaticInitFailure

{

public static void main(String args[])

{

System.out.println("Please Enter a number : ");
int palindrome = new Scanner(System.in).nextInt();
if(isPalindrome(palindrome))

{
System.out.println("Number : " + palindrome + " is a palindrome");
}

else

{
System.out.println("Number : " + palindrome + " is not a palindrome");
}
}
public static boolean isPalindrome(int number)

{
int palindrome = number;
int reverse = 0;

while (palindrome != 0)

{
int remainder = palindrome % 10;
reverse = reverse * 10 + remainder;
palindrome = palindrome / 10;
}

if (number == reverse)

{
return true;
}
return false;
}
}

Palindrome string in java

public class Palindrome

private String pal;

public Palindrome(String initPal)

   pal = initPal.toUpperCase();

   public boolean isPalindrome()

       if (pal.length() <= 1)

       return true;

            char first = pal.charAt(0);

   char last = pal.charAt(pal.length()-1);

   if (Character.isLetter(first) &&

   Character.isLetter(last))

       if (first != last)

               return false;

       else

               Palindrome sub = new Palindrome(pal.substring(1,pal.length()-1));

               return sub.isPalindrome();

   else if (!Character.isLetter(first))

       Palindrome sub = new Palindrome(pal.substring(1));

       return sub.isPalindrome();

   else

       Palindrome sub = new Palindrome(pal.substring(0,pal.length()-1));

       return sub.isPalindrome();

             public static void main(String[] args)

   Palindrome p1 = new Palindrome("Madam, I'm Adam.");

   System.out.println(p1.isPalindrome());

   Palindrome p2 = new Palindrome("Nope!");

   System.out.println(p2.isPalindrome());

   Palindrome p3 = new Palindrome("dad");

   System.out.println(p3.isPalindrome());

   Palindrome p4 = new Palindrome("Go hang a salami, I'm a lasagna hog.");

   System.out.println(p4.isPalindrome());

package beginnersbook.com;

import java.util.Scanner;

class PalindromeCheck

 public static boolean isPal(String s)

        if(s.length() == 0 || s.length() == 1)

            return true;

        if(s.charAt(0) == s.charAt(s.length()-1))

        return isPal(s.substring(1, s.length()-1));

                  return false;

             public static void main(String[]args)

        Scanner scanner = new Scanner(System.in);

        System.out.println("Enter the String for check:");

        String string = scanner.nextLine();

        if(isPal(string))

            System.out.println(string + " is a palindrome");

        else

            System.out.println(string + " is not a palindrome");