error in object array

• • Reply

  14 years ago

  by peeratep

  peeratep

  , Thailand

  Joined 14 years ago

  import java.util.*;
  import java.util.*;
  
  class Data{
  private String str;
  private double d;
  private char ch;
  
  public char getCh() {
  return this.ch;
  }
  
  public void setCh(char ch) {
  this.ch = ch;
  }
  
  public double getD() {
  return this.d;
  }
  
  public void setD(double d) {
  this.d = d;
  }
  
  public String getStr() {
  return this.str;
  }
  
  public void setStr(String str) {
  this.str = str;
  }
  
  
  }
  
  public class TestData{
  
  public static void main(String[] args){
  try{
  
  Data[] dataArray = new Data[1];
  
  dataArray[0].setStr("AAA");
  dataArray[0].setD(10.0);
  dataArray[0].setCh('Z');
  
  System.out.println(dataArray[0].getStr());
  System.out.println(dataArray[0].getD());
  System.out.println(dataArray[0].getCh());
  
  }catch(NullPointerException e){
  System.out.println(e);
  }
  }
  
  
  }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  // error java.lang.NullPointerException
  
  

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• • Reply

  14 years ago

  by qwijibow

  Chris Stones

  England Nottingham, United Kingdom

  Joined 19 years ago
  
  Java is quite strange when it comes to arrays, and doesnt really make suence unless you understand pointers to pointers in c/c++.
  
  In Java, to Create an Array or N objects..
  
  // Create an Array of Objects...
  Object[] Array = new Object;
  
  // Fill The Array With Object.
  for(int I=0; I<N;I++)
  {
       Array[I] = new Object;
  }
  
  
  
  
  In Your Code, You Create An Array (pointer to pointers)
  but dont create new objects inside the array... and therefor, causing a memory access violation.
  
  
  HOWEVER,,, your array is only 1 object in size... you dont need an array.,, just create the new object.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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