Problem when calling a method

Question

hello,
I have a problem when Im trying to call the make method that in the Tree class.
Im calling it from the main method like you can see and It writes:
-Cannot make a static reference to the non-static method make() from the type Tree.
Can anyone help me please and tell me what is the problem?
Im using Eclipse 3.1.2
Thank you.
//import java.lang.Object;
//import java.lang.reflect.Array;
//structure of the node
class mainClass extends Tree {
     public static void main(String args[]){
          Tree.make();
          //char temporary[]=new char[9];
          //Tic_Tac_Toe pointersToNodes[]=new Tic_Tac_Toe[9];
          //for(j=0;j<9;j++)
               //temporary[j]='b';     
public class Tic_Tac_Toe {
     char currentCaseVector[]=new char[9];
     Tic_Tac_Toe PointersToNodes[]=new Tic_Tac_Toe[9];
     int evaluation;
//class that builds the game tree
class Tree {
     public Tic_Tac_Toe T1=new Tic_Tac_Toe();
     //char currentCaseVector[]=new char[9];
     public char currentSign;
     Tree(){
         resetCurrentCaseArray(T1);
         //T1.currentCaseVector.setSize(9);
          //System.out.println(T1.currentCaseVector.elementAt(2));
     void make(){
          Tic_Tac_Toe T = new Tic_Tac_Toe();
          int howMuchCloser,i;
          Tree tree=new Tree();
          for(i=0;i<9;i++)
               T.currentCaseVector='b';
          howMuchCloser=1;
          for(i=0;i<9;i++){
               T.PointersToNodes[findAvailablePlaceOnPointersToNodes(T)]=tree.buildNewTree(1,'o',T.currentCaseVector,howMuchCloser);
               howMuchCloser++;
     Tic_Tac_Toe buildNewTree(int i,char currentSign,char temp[],int howMuchCloser)throws ArrayIndexOutOfBoundsException{
          int j=0;
          //int howMuchCloser=1;
          //for(j=i;j<9;j++){
          Tic_Tac_Toe T1=new Tic_Tac_Toe();
          currentSign=changeSign(currentSign);
          resetCurrentCaseArray(T1);
          //try{
          setBoard(T1.currentCaseVector,temp,howMuchCloser,currentSign);
          //catch(ArrayIndexOutOfBoundsException e){
               //System.out.print("ArrayIndexOutOfBoundsException");
               //System.out.println(i);          
          printTest(T1);
          temp=T1.currentCaseVector;
          howMuchCloser=1;
          if((isFull(T1.currentCaseVector))==true)
               return T1;
          if(checkWin(T1)){
               return T1;
          //printTest(T1);
               //break;
          for(j=i;j<9;j++){
               T1.PointersToNodes[findAvailablePlaceOnPointersToNodes(T1)]=buildNewTree(i+1,currentSign,temp,howMuchCloser);                              
               howMuchCloser++;
                    //if(checkIfBlankEqualOne(T1.currentCaseVector)==false)
               //howMuchCloser++;
               //T1.PointersToNodes[findAvailablePlaceOnPointersToNodes(T1)]=buildNewTree(i+1,currentSign,temp);
     return T1;
     int findCloser(char charArray[],int howMuchCloser){
          int i;
          for(i=0;i<9;i++){
               if (charArray[i]=='b'){
                    howMuchCloser--;
               else
                    continue;
               if (howMuchCloser==0)
                    break;     
          return i;
     void setBoard(char current[],char previous[],int howMuchCloser,char iksOrCircle){
               int i;
               for(i=0;i<9;i++){
                    current[i]=previous[i];/******/
               current[findCloser(current,howMuchCloser)]=iksOrCircle;
     char changeSign(char sign){
          if(sign=='x')
               return 'o';
          else
               return 'x';
     boolean isFull(char array[]){
          int i;
          for(i=0;i<9;i++){
               if(array[i]=='b'){
                    return false;
          return true;
     void resetCurrentCaseArray(Tic_Tac_Toe T1){
          for(int i=0;i<9;i++)
               T1.currentCaseVector[i]='b';
     boolean checkWin(Tic_Tac_Toe T1){
          int count1=0;
          int count2=0;
          //checking columns
          int i,j;
          for(i=0;i<3;i++){
               for(j=i;j<(i+7);j+=3){
                    if(T1.currentCaseVector[j]=='x')
                         count1++;
                    if(T1.currentCaseVector[j]=='o')
                         count2++;
               if(count1==3)
                    return true;
               if(count2==3)
                    return true;
               count1=0;
               count2=0;
          //checking rows
          for(i=0;i<7;i+=3){
               for(j=i;j<(i+3);j++){
                    if(T1.currentCaseVector[j]=='x')
                         count1++;
                    if(T1.currentCaseVector[j]=='o')
                         count2++;
               if(count1==3)
                    return true;
               if(count2==3)
                    return true;
               count1=0;
               count2=0;
          //checking diagonal
          for(i=0;i<9;i+=4){
               if(T1.currentCaseVector[i]=='x')
                    count1++;
               if(T1.currentCaseVector[i]=='o')
                    count2++;
          if(count1==3)
               return true;
          if(count2==3)
               return true;
          count1=0;
          count2=0;
          for(i=2;i<7;i+=2){
               if(T1.currentCaseVector[i]=='x')
                    count1++;
               if(T1.currentCaseVector[i]=='o')
                    count2++;
          if(count1==3)
               return true;
          if(count2==3)
               return true;
          return false;
     public int findAvailablePlaceOnPointersToNodes(Tic_Tac_Toe tic_tac_toe){
          int i;
          for(i=0;i<9;i++)
               if(tic_tac_toe.PointersToNodes[i]==null)
                    return i;
          return -1;
     void printTest(Tic_Tac_Toe T1){
          for(int i=0;i<9;i++)
               System.out.println(T1.currentCaseVector[i]);
     boolean checkIfBlankEqualOne(char array[]){
          for(int i=0;i<9;i++){
               if(i<8)
                    if(array[i]=='b')
                         return false;
          if(array[8]=='b')
               return true;
          return false;
     /*void makeFirst(char temporary[]){
          for(int i=0;i<9;i++)
               temporary[i]='b';

Answer 1

I have two things in mind:
1. either modify the make() in class Tree as static
static void make() {//caution u may have to worry about instance variables referenced under this method2.
under your main static method, invoke it like this instead
mainClass mc=new mainClass();
mc.make();//not Tree.make();