プログラムは非常にうまくコンパイルされますが、ドロップを実行すると文字列入力でエラー

Question

が非常にうまくコンパイルされますが、実行時にメソッドUserInputWindowsの文字列入力でエラーが発生します。私は問題のない前にこのようなwhileループを書いたが、私は今なぜエラーになっているのか理解できないようだ。プログラムはどこにもありませんでした。私はちょうど私が何かエラーがあるかどうかを確認するためにそれを本当に走った。ここではそれは、単純なタイプミスだ

enter code here 
import java.util.Scanner; 

public class PaintEstimate 
{ 
final static double WallAndCeilingPaintCost = 18.50;//cost for 1 gallon 
//final static double WhiteEnamelPaintCost = 9.50; //cost for 1 quart//using only for refrence now//changed to _MoldingCostPerQuart 
//final static double ColorEnamelPaintCost = 12.50; //cost for 1 quart//using only for refrence now// changed to _MoldingCostPerQuart 
final static double CoverageOfWallAndCeilingPaint = 250.00; // coverage of wall and ceiling paint in sqft 
final static double CoverageOfEnamelPaint = 100.00;// coverage of enamel paint both color and whit in linear sqft 

public static double IntchesToFeet; 
public static double RoomSquareFeet, CeilingSqaureFeet; 
public static double InchRoomWidth, InchRoomLength, InchRoomHeight; 
public static double FeetRoomWidth, FeetRoomLength, FeetRoomHeight; 
public static double NumberOfWindows, NumberOfDoors; 
public static double InchesWindowsHeight, InchesWindowsLength, InchesWindowsMoldingWidth; 
public static double InchesDoorsHeight, InchesDoorsLength, InchesDoorsMoldingWidth; 
public static String WindowsMoldingColorOrWhite, DoorsMoldingColorOrWhite; 
public static double WindowsMoldingCostPerQuart = 0; 
public static double DoorsMoldingCostPerQuart = 0; 
public static Scanner scan = new Scanner(System.in); 

public static void main(String[] args) 
{ 
    Scanner scan = new Scanner(System.in); 
    UserInputWallsAndCeiling(); 
    UserInputWindows(); 
    UserInputDoors(); 
} 
public static void UserInputWallsAndCeiling() 
{ 
    System.out.println("What is the room height in inches? "); 
    InchRoomHeight = scan.nextDouble(); 
    System.out.println("What is the room width in inches? "); 
    InchRoomWidth = scan.nextDouble(); 
    System.out.println("What is the room length in inches? "); 
    InchRoomWidth = scan.nextDouble(); 
} 
public static void UserInputWindows() 
{ 
    System.out.println("How many windows are in the room? "); 
    NumberOfWindows = scan.nextDouble(); 
    if(NumberOfWindows > 0) 
     { 
      System.out.println("What are the windows height in inches? "); 
      InchesWindowsHeight = scan.nextDouble(); 
      System.out.println("What are the windows length in inches? "); 
      InchesWindowsLength = scan.nextDouble(); 
      System.out.println("What are the windows molding width in inches? "); 
      InchesWindowsMoldingWidth = scan.nextDouble(); 
      System.out.println("Is the windows molding color or white? "); 

      boolean WindowsTrue = false; 
      while (!WindowsTrue) 
       { 
        System.out.println("Is the doors molding color or white? "); 
        DoorsMoldingColorOrWhite = scan.nextLine(); 
        if (WindowsMoldingColorOrWhite.equals("color")) 
         { 
          WindowsMoldingCostPerQuart = 12.50; 
          WindowsTrue = true; 
         } 
        else if (WindowsMoldingColorOrWhite.equals("white")) 
         { 
          WindowsMoldingCostPerQuart = 9.50; 
          WindowsTrue = true; 
         } 
        else 
         { 
          System.out.println("Please enter if the molding is color or white"); 
         } 
       } 
     } 
} 
public static void UserInputDoors() 
{ 
    System.out.print("How many doors are in the room? "); 
    NumberOfDoors = scan.nextDouble(); 
    if(NumberOfDoors > 0) 
     { 
      System.out.println("What are the doors height in inches? "); 
      InchesDoorsHeight = scan.nextDouble(); 
      System.out.println("What are the doors length in inches? "); 
      InchesDoorsLength = scan.nextDouble(); 
      System.out.println("What are the doors molding width in inches? "); 
      InchesDoorsMoldingWidth = scan.nextDouble(); 

      boolean DoorsTrue = false; 
      while (!DoorsTrue) 
       { 
        System.out.println("Is the doors molding color or white? "); 
        DoorsMoldingColorOrWhite = scan.nextLine(); 
        if (DoorsMoldingColorOrWhite.equals("color")) 
         { 
          DoorsMoldingCostPerQuart = 12.50; 
          DoorsTrue = true; 
         } 
        else if (DoorsMoldingColorOrWhite.equals("white")) 
         { 
          DoorsMoldingCostPerQuart = 9.50; 
          DoorsTrue = true; 
         } 
        else 
         { 
          System.out.println("Please enter if the molding is color or white"); 
         } 
       } 
      //System.out.print(InchesDoorsHeight + " " + InchesDoorsLength + " " + DoorsMoldingColorOrWhite + " " + DoorsMoldingCostPerQuart) 
     } 
} 
public static void IntchesToFeet() 
{ 
    FeetRoomWidth= InchRoomWidth/12; 
    FeetRoomLength = InchRoomLength/12; 
    FeetRoomHeight = InchRoomHeight/12; 
} 

}

Answer 1

以下コーダ;）

System.out.println("Is the doors molding color or white? "); 
DoorsMoldingColorOrWhite = scan.nextLine(); 
if (WindowsMoldingColorOrWhite.equals("color")) { 
     //... 
} 

ドアのWindows成形対成形

あなたが出てくるNullPointerExceptionが確認した場合このコードの行は、そのIF文を直接指しています。 tはその行で、または前に検索を開始することを示しています。：

エラーと何である何

スレッドでの例外PaintEstimate.UserInputWindowsで「メイン」のjava.lang.NullPointerException（PaintEstimate.java:61）