java - Delete a node from a binary search tree -

i new binary search trees , deleting node giving me problems. tried draw out problem see doing wrong , still cannot seem see problem , not want copy code website.

i understand how delete node 1 child or no children , think code correct methods. problem deleting node 2 children. cannot work properly. or advice appreciated.

  public void deletenode(int number) {          if (root == null)           {             joptionpane.showmessagedialog(null," tree empty, can not delete ", joptionpane.warning_message);                 return;          }          node child = root;          node parent = root;           while (number != child.data) {             if (number < child.data)              {                 parent = child;                 child = child.left;             }             else if (number > child.data)              {                 parent = child;                 child = child.right;             }             if(child == null){                 joptionpane.showmessagedialog(null," number not found",joptionpane.warning_message);                         return;             }          }           if(child.right == null && child.left == null)          {             hasnochildren(child, parent);          }         else if(child.left != null && child.right != null)          {             hastwochildren(child, parent);          }          else if (child.right != null && child.left == null)          {              hasrightchild(child, parent);          }          else if (child.left != null && child.right == null)          {             hasleftchild(child, parent);          } } 

this method delete node 2 children

public void hastwochildren(node child, node parent) {     node temp = null;      if(child.data < parent.data){          node childorg = child;          temp = child;          child = child.left;          while(child.right != null){              temp = child;              child = child.right;          }          childorg.data = child.data;          if (child.left != null && child.right == null)          {             hasleftchild(child, temp);          }else{              temp.right = null;          }      }      else       {          node childorg = child;          temp = child;          child = child.right;          while(child.left != null){              temp = child;              child = child.left;          }          childorg.data = child.data;          if (child.left != null && child.right == null)          {             hasrightchild(child, temp);          }else{              temp.left = null;          }      } } 

these methods delete node no children or 1 child

public void hasnochildren(node child, node parent) {     if(child.data == root.data)      {          root = null;      }      else if(child.data < parent.data){          parent.left = null;      }else{          parent.right = null;      } } public void hasleftchild(node child, node parent){     if(child.data < parent.data){             parent.left = child.left;      }else{          parent.right = child.left;      } }  public void hasrightchild(node child, node parent){     if(child.data < parent.data){             parent.left = child.right;      }else{          parent.right = child.right;      } } 

here complete binary tree deletion implementation possible cases :

public boolean delete(node nodetodelete) {     boolean succes = false;     node nodetoremove = findthenodetodelete(nodetodelete);     if (nodetoremove == null) {         return succes;     }     // case1; if node has no children     if (nodetoremove.left == null && nodetoremove.right == null) {         if (nodetoremove.parent.left.data == nodetodelete.data) {             nodetoremove.parent.left = null;             nodetoremove = null;             succes = true;             return succes;         } else if (nodetoremove.parent.right.data == nodetodelete.data) {             nodetoremove.parent.right = null;             nodetoremove = null;             succes = true;             return succes;          }         // case 2: if has 1 children     } else if ((nodetoremove.left == null && nodetoremove.right != null)             || (nodetoremove.right == null && nodetoremove.left != null)) {         if (nodetoremove.left != null) {             nodetoremove.parent.left = nodetodelete.left;             nodetodelete = null;             succes = true;             return succes;          } else if (nodetoremove.parent.right != null) {             nodetoremove.parent.right = null;             nodetoremove = null;             succes = true;             return succes;         }     }     // case 3 :     if (nodetoremove.left != null && nodetoremove.right != null) {          node minleftnode = findtheleftmostnodefromtherightsubtree(nodetoremove.right);          system.out.println("----" + minleftnode.data);          // if parent of node not null means         // root         // assign left mode min root ,         // min.right=notetoremove.right;          // derefrence min node /remove tree         minleftnode.parent.left = null;         minleftnode.parent = null;         node parentofthenodetodelete = nodetoremove.parent;          minleftnode.parent = parentofthenodetodelete;         node rightofnodetodelete = nodetoremove.right;         node leftofnodetodelete = nodetoremove.left;          if (parentofthenodetodelete == null) {             root = minleftnode;         } else {             if (parentofthenodetodelete.right.data == nodetodelete.data) {                 parentofthenodetodelete.right = minleftnode;              } else if (parentofthenodetodelete.left.data == nodetodelete.data) {                 parentofthenodetodelete.left = minleftnode;              }          }         minleftnode.right = rightofnodetodelete;         minleftnode.left = leftofnodetodelete;         nodetoremove = null;     }      return succes; }