Size() and tostring() are not fully implemented

can u help me fix this problem ?

9 2 10 * public class ArrayStack implements s 12 { 13 private final static int DEFAULI 14 15 private int top; 16 private T[l stack; jsjf.ArrayStack_o toString> Output x Usages Java Call Hierarchy Debugger Console - Ch12 (run) X on ty und cun Stack Menu Selections 1.push 2. pop 3.peek 4.display 5. Eacit I Enter your choice: 1 Enter element iliam Stack Menu Selections 1.push 2.pop 3.peek 4.display 5. Exis Enter your choice: 1 45 ans, 5th Edition, Lewis/DePasquale/Chase Audio Fixed1 verseCharacter ockTest f ArrayStack.java ArrayTest.java StackADT.java jf.exceptions Empty CollectionException.java Packages aries tLibraries Demoich12 Demo2ch12 D Source History 78893 1 package jajt: 2 3 import jajt.exceptions.; 4 import java.util.Arrays; 5 6 7 An array implementation of a stack in which 8 stack is fixed at index 0 9 10 * public class ArrayStack implements StackADTT) 12 { 13 private final static int DEFAULT_CAPACITY 14 15 private int top; private T[] stack: jsjf.ArrayStack > OtoString> Output x Usages Java Cal Rierarchy Debugger Console x Ch12 (run) 2.pop pe 4.display .. 16 implements s 12 { 13 private final static int DEFAULI 14 15 private int top; 16 private T[l stack; jsjf.ArrayStack_o toString> Output x Usages Java Call Hierarchy Debugger Console - Ch12 (run) X on ty und cun Stack Menu Selections 1.push 2. pop 3.peek 4.display 5. Eacit I Enter your choice: 1 Enter element iliam Stack Menu Selections 1.push 2.pop 3.peek 4.display 5. Exis Enter your choice: 1 45 ans, 5th Edition, Lewis/DePasquale/Chase Audio Fixed1 verseCharacter ockTest f ArrayStack.java ArrayTest.java StackADT.java jf.exceptions Empty CollectionException.java Packages aries tLibraries Demoich12 Demo2ch12 D Source History 78893 1 package jajt: 2 3 import jajt.exceptions.; 4 import java.util.Arrays; 5 6 7 An array implementation of a stack in which 8 stack is fixed at index 0 9 10 * public class ArrayStack implements StackADTT) 12 { 13 private final static int DEFAULT_CAPACITY 14 15 private int top; private T[] stack: jsjf.ArrayStack > OtoString> Output x Usages Java Cal Rierarchy Debugger Console x Ch12 (run) 2.pop pe 4.display .. 16