java - How do I remove a node in a BST without duplicating nodes? -

my code below. i'm having trouble deletion method, can not delete node in binary search tree , replace without creating 2 of replacement nodes... how can fix this?

public class bstmain { public static void deletevalue(int num, bstnode root){     bstnode cursor = root;     while(true){ //move cursor         while(cursor.getleft()!=null && num<cursor.getdata()){             //move cursor             cursor = cursor.getleft();         }         while(cursor.getright()!=null && num>cursor.getdata()){             //move cursor             cursor = cursor.getright();         }         if(cursor.getdata() == num || (cursor.getleft()==null && num<cursor.getdata()) || (cursor.getright()==null && num>cursor.getdata())) //check placing cases              break; //time delete node in tree     }     if(cursor.getdata()==num){//delete node         if(cursor.getleft()!=null){ //if left exists             bstnode cursor2 = cursor.getleft();             while(cursor2.getright()!=null){ //get rightmost of left replace                 cursor2 = cursor2.getright();             }             cursor.setdata(cursor2.getdata()); //replace cursor             if(cursor2.getleft()!=null)                 cursor2.getleft().root = cursor2.root; //replace cursor2             cursor2.root.setright(cursor2.getleft());         } else if(cursor.getright()!=null){ //if no left right             bstnode cursor2 = cursor.getright();              while(cursor2.getleft()!=null){ //get leftmost of right                 cursor2 = cursor2.getleft();             }             cursor.setdata(cursor2.getdata()); //replace cursor             if(cursor2.getright()!=null)                 cursor2.getright().root = cursor2.root; //replace cursor2             cursor2.root.setleft(cursor2.getright());         } else {             system.out.println("node " + num + " not exist!");         }     }     else system.out.println(num + " not exist in binary search tree!"); } } 

some output:
in order: 19 20 21 22 23 23 45
command: d 19
after deletion: 20 20 21 22 23 23 45
command: d 20
after deletion: 20 20 21 22 23 23 45
command: d 21
after deletion: 20 20 22 23 23 45
command: d 22
after deletion: 20 20 20 20 23 23 45
command: d 23
after deletion: 20 20 20 20 23 23 20 20 20 20 45
command: d 45
after deletion: 20 20 20 23 23 20 20 20 20
command: d 20
after deletion: 20 20 20 23 23 20 20 20
command: d 20
after deletion: 20 20 20 23 23 20 20
command: d 20
after deletion: 20 20 20 23 23 20
command: d 20
after deletion: 20 20 20 23 23 23 20 20 20 23
command: d 23
after deletion: 20 20 20 23 23 23 20 20 20 23
command: e