Codigo cesar Encriptado y desencriptado

package codigocesar;
/**
 *
 * @author LuisEmm
 */
public class CodigoCesar {

   
    public static void main(String[] args) {
       
        Integer clave=3;
        String frase1="lapiz";
        String frase2="";
        String frase3="";
        char[] charfrase1=frase1.toCharArray();
       
        char[] may= {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z' };
        char[] min= {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
       
        int largo_frase=charfrase1.length;
       
        int largo_array=may.length;
       
        int residuo;
        System.out.println(charfrase1);
       
       
        for (int i=0;i<largo_frase;i++)
        {
            for (int j=0;j<min.length;j++)
            {
                while (clave>26)
                {
                    clave -= 26;
                }
               
                if (charfrase1[i]==min[j])
                {
                    if((j+clave)>25)
                    {
                        residuo= j%26;
                        frase3=frase3 + min[residuo];
                       
                        System.out.print(residuo+"\n");
                      
                     
                        frase2=frase2 + min[j+clave-26];
                    }else{
                        residuo= j%26;
                        frase3=frase3 + min[residuo];
                        System.out.print(residuo+"\n");
                       
                     
                        frase2=frase2 + min[j+clave];
                    }
                }
                   
                if (charfrase1[i]==may[j])
                {
                    if((j+clave)>25)
                    {
                        residuo= j%26;
                        frase3=frase3 + min[residuo];
                        System.out.print(residuo+"\n");
                       
                        frase2=frase2 + min[j+clave-26];
                    }else{
                        residuo= j%26;
                        frase3=frase3 + min[residuo];
                        System.out.print(residuo+"\n");
                       
                        frase2=frase2 + min[j+clave];
                    }
                }
            }
      
        }
       
         System.out.print("Frase Encriptada: " + frase2 +"\n");
         System.out.print("Frase desencriptada: " + frase3 +"\n");
       
    }
   
}