错误：异常在线程“主要” java.lang.Error的：未解决的编译问题

Question

我在看初学者Java教程，并在编写代码我得到了一些错误：

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    Syntax error, 'for each' statements are only available if source level is 1.5 or greater 
    Arrays cannot be resolved 
    Arrays cannot be resolved 
    Arrays cannot be resolved 

    at Animal.main(Animal.java:389) 

我的代码：

Animal.Java：

import java.util.Scanner; 


// A class defines the attributes (fields) and capabilities (methods) of a real world object 

public class Animal { 

    // static means this number is shared by all objects of type Animal 
    // final means that this value can't be changed 
    public static final double FAVNUMBER = 1.6180; 

    // Variables (Fields) start with a letter, underscore or $ 
    // Private fields can only be accessed by other methods in the class 

    // Strings are objects that hold a series of characters 
    private String name; 

    // An integer can hold values from -2^31 to (2^31) -1 
    private int weight; 

    // Booleans have a value of true or false 
    private boolean hasOwner = false; 

    // Bytes can hold the values between -128 to 127 
    private byte age; 

    // Longs can hold the values between -2^63 to (2^63) - 1 
    private long uniqueID; 

    // Chars are unsigned ints that represent UTF-16 codes from 0 to 65,535 
    private char favoriteChar; 

    // Doubles are 64 bit IEEE 754 floating points with decimal values 
    private double speed; 

    // Floats are 32 bit IEEE 754 floating points with decimal values 
    private float height; 

    // Static variables have the same value for every object 
    // Any variable or function that doesn't make sense for an object to have should be made static 
    // protected means that this value can only be accessed by other code in the same package 
    // or by subclasses in other packages 

    protected static int numberOfAnimals = 0; 

    // A Scanner object allows you to except user input from the keyboard 
    static Scanner userInput = new Scanner(System.in); 

    // Any time an Animal object is created this function called the constructor is called 
    // to initialize the object 
    public Animal(){ 

     // Shorthand for numberOfAnimals = numberOfAnimals + 1; 
     numberOfAnimals++; 

     int sumOfNumbers = 5 + 1; 
     System.out.println("5 + 1 = " + sumOfNumbers); 

     int diffOfNumbers = 5 - 1; 
     System.out.println("5 - 1 = " + diffOfNumbers); 

     int multOfNumbers = 5 * 1; 
     System.out.println("5 * 1 = " + multOfNumbers); 

     int divOfNumbers = 5/1; 
     System.out.println("5/1 = " + divOfNumbers); 

     int modOfNumbers = 5 % 3; 
     System.out.println("5 % 3 = " + modOfNumbers); 

     // print is used to print to the screen, but it doesn't end with a newline \n 
     System.out.print("Enter the name: \n"); 

     // The if statement performs the actions between the { } if the condition is true 
     // userInput.hasNextLine() returns true if a String was entered in the keyboard 
     if(userInput.hasNextLine()){ 

      // this provides you with a way to refer to the object itself 
      // userInput.nextLine() returns the value that was entered at the keyboard 
      this.setName(userInput.nextLine()); 

      // hasNextInt, hasNextFloat, hasNextDouble, hasNextBoolean, hasNextByte, 
      // hasNextLong, nextInt, nextDouble, nextFloat, nextBoolean, etc. 

     } 

     this.setFavoriteChar(); 
     this.setUniqueID(); 

    } 

    // It is good to use getter and setter methods so that you can protect your data 
    // In Eclipse Right Click -> Source -> Generate Getter and Setters 

    public String getName() { 
     return name; 
    } 

    public void setName(String name) { 
     this.name = name; 
    } 

    public int getWeight() { 
     return weight; 
    } 

    public void setWeight(int weight) { 
     this.weight = weight; 
    } 

    public boolean isHasOwner() { 
     return hasOwner; 
    } 

    public void setHasOwner(boolean hasOwner) { 
     this.hasOwner = hasOwner; 
    } 

    public byte getAge() { 
     return age; 
    } 

    public void setAge(byte age) { 
     this.age = age; 
    } 

    public long getUniqueID() { 
     return uniqueID; 
    } 

    // Method overloading allows you to accept different input with the same method name 
    public void setUniqueID(long uniqueID) { 
     this.uniqueID = uniqueID; 

     System.out.println("Unique ID set to: " + this.uniqueID); 
    } 

    public void setUniqueID() { 

     long minNumber = 1; 
     long maxNumber = 1000000; 

     // Generates a random number between 1 and 1000000 
     this.uniqueID = minNumber + (long)(Math.random() * ((maxNumber - minNumber) + 1)); 

     // You can cast from one primitive value into another by putting what you want between () 
     // (byte) (short) (long) (double) 
     // (float), (boolean) & (char) don't work. 
     // (char) stays as a number instead of a character 

     // You convert from a primitive to a string like this 
     String stringNumber = Long.toString(maxNumber); 

     // Byte.toString(bigByte); Short.toString(bigShort); Integer.toString(bigInt); 
     // Float.toString(bigFloat); Double.toString(bigDouble); Boolean.toString(trueOrFalse); 

     // You convert from a String to a primitive like this 
     int numberString = Integer.parseInt(stringNumber); 

     // parseShort, parseLong, parseByte, parseFloat, parseDouble, parseBoolean 

     System.out.println("Unique ID set to: " + this.uniqueID); 
    } 

    public char getFavoriteChar() { 
     return favoriteChar; 
    } 

    public void setFavoriteChar(char favoriteChar) { 
     this.favoriteChar = favoriteChar; 
    } 

    public void setFavoriteChar() { 

     int randomNumber = (int) (Math.random() * 126) + 1; 

     this.favoriteChar = (char) randomNumber; 

     // if then else statement 
     // > < == != >= <= 
     if(randomNumber == 32){ 

      System.out.println("Favorite character set to: Space"); 

     } else if(randomNumber == 10){ 

      System.out.println("Favorite character set to: New Line"); 

     } else { 

      System.out.println("Favorite character set to: " + this.favoriteChar); 

     } 

     // Logical operators 
     // ! : Converts the boolean value to its right to its opposite form ie. true to false 
     // & : Returns true if boolean value on the right and left are both true (Always evaluates both boolean values) 
     // && : Returns true if boolean value on the right and left are both true (Stops evaluating after first false) 
     // | : Returns true if either boolean value on the right or left are true (Always evaluates both boolean values) 
     // || : Returns true if either boolean value on the right or left are true (Stops evaluating after first true) 
     //^: Returns true if there is 1 true and 1 false boolean value on the right or left 

     if((randomNumber > 97) && (randomNumber < 122)){ 

      System.out.println("Favorite character is a lowercase letter"); 

     } 

     if(((randomNumber > 97) && (randomNumber < 122)) || ((randomNumber > 64) && (randomNumber < 91))){ 

      System.out.println("Favorite character is a letter"); 

     } 

     if(!false){ 

      System.out.println("I turned false to " + !false); 

     } 

     // The ternary operator assigns one or another value based on a condition 
     int whichIsBigger = (50 > randomNumber) ? 50 : randomNumber; 

     System.out.println("The biggest number is " + whichIsBigger); 

     // The switch statement is great for when you have a limited number of values 
     // and the values are int, byte, or char unless you have Java 7 which allows Strings 
     switch(randomNumber){ 

     case 8 : 
      System.out.println("Favorite character set to: Backspace"); 
      break; 

     case 9 : 
      System.out.println("Favorite character set to: Horizontal Tab"); 
      break; 

     case 10 : 
     case 11 : 
     case 12 : 
      System.out.println("Favorite character set to: Something else weird"); 
      break; 

     default : 
      System.out.println("Favorite character set to: " + this.favoriteChar); 
      break; 

     } 

    } 

    public double getSpeed() { 
     return speed; 
    } 

    public void setSpeed(double speed) { 
     this.speed = speed; 
    } 

    public float getHeight() { 
     return height; 
    } 

    public void setHeight(float height) { 
     this.height = height; 
    } 

    protected static int getNumberOfAnimals() { 
     return numberOfAnimals; 
    } 

    // Since numberOfAnimals is Static you must set the value using the class name 
    public void setNumberOfAnimals(int numberOfAnimals) { 
     Animal.numberOfAnimals = numberOfAnimals; 
    } 

    protected static void countTo(int startingNumber){ 

     for(int i = startingNumber; i <= 100; i++){ 

      // continue is used to skip 1 iteration of the loop 
      if(i == 90) continue; 

      System.out.println(i); 

     } 

    } 

    protected static String printNumbers(int maxNumbers){ 

     int i = 1; 
     while(i < (maxNumbers/2)){ 

      System.out.println(i); 
      i++; 

      // This isn't needed, but if you want to jump out of a loop use break 
      if(i == (maxNumbers/2)) break; 

     } 

     Animal.countTo(maxNumbers/2); 

     // You can return a value like this 
     return "End of printNumbers()"; 

    } 

    protected static void guessMyNumber(){ 

     int number; 

     // Do while loops are used when you want to execute the code in the braces at least once 
     do { 

      System.out.println("Guess my number up to 100"); 

      // If what they entered isn't a number send a warning 
      while(!userInput.hasNextInt()){ 

       String numberEntered = userInput.next(); 
       System.out.printf("%s is not a number\n", numberEntered); 

      } 
      number = userInput.nextInt(); 

     }while(number != 50); 

     System.out.println("Yes the number was 50"); 

    } 

    // This will be used to demonstrate polymorphism 
    public String makeSound(){ 

     return "Grrrr"; 

    } 

    // With polymorphism we can refer to any Animal and yet use overridden methods 
    // in the specific animal type 
    public static void speakAnimal(Animal randAnimal){ 

     System.out.println("Animal says " + randAnimal.makeSound()); 

    } 

    // public allows other classes to use this method 
    // static means that only a class can call for this to execute 
    // void means it doesn't return a value when it finishes executing 
    // This method can except Strings that can be stored in the String array args when it is executed 

    public static void main(String[] args){ 

     Animal theDog = new Animal(); 

     System.out.println("The animal is named " + theDog.getName()); 

     System.out.println(Animal.printNumbers(100)); 

     Animal.countTo(100); 

     Animal.guessMyNumber(); 

     // An array is a fixed series of boxes that contain multiple values of the same data type 
     // How you create arrays 
     // int[] favoriteNumbers; 
     // favoriteNumbers = new int[20]; 

     int[] favoriteNumbers = new int[20]; 

     favoriteNumbers[0] = 100; 

     String[] stringArray = {"Random", "Words", "Here"}; 

     // for(dataType[] varForRow : arrayName) 
     for(String word : stringArray) 
     { 

      System.out.println(word); 

     } 

     // This is a multidimensional array 
     String[][][] arrayName = { { { "000" }, { "100" }, { "200" }, { "300" } }, 
       { { "010" }, { "110" }, { "210" }, { "310" } }, 
       { { "020" }, { "120" }, { "220" }, { "320" } }}; 

     for(int i = 0; i < arrayName.length; i++) 
     { 
      for(int j = 0; j < arrayName[i].length; j++) 
      { 

       for(int k = 0; k < arrayName[i][j].length; k++) 
       { 
        System.out.print("| " + arrayName[i][j][k] + " "); 

       } 
      } 

      System.out.println("|"); 

     } 

     // You can copy an array (stringToCopy, indexes to copy) 
     String[] cloneOfArray = Arrays.copyOf(stringArray, 3); 

     // You can print out the whole array 
     System.out.println(Arrays.toString(cloneOfArray)); 

     // Returns the index or a negative number 
     System.out.println(Arrays.binarySearch(cloneOfArray, "Random")); 

    } 
} 

Dog.Java

public class Dog extends Animal{ 

    public Dog() { 


    } 

    // You can override Animal methods 
    public String makeSound(){ 

     return "Woof"; 

    } 

    public static void main(String[] args) { 

     Dog fido = new Dog(); 

     fido.setName("Fido"); 

     System.out.println(fido.getName()); 

    } 

} 

Cat.java

public static void main(String[] args) { 

     Animal fido = new Dog(); 

     Animal fluffy = new Cat(); 

     // We can have an array of Animals that contain more specific subclasses 
     // Any overridden methods are used instead because of polymorphism 
     Animal[] theAnimals = new Animal[10]; 

     theAnimals[0] = fido; 
     theAnimals[1] = fluffy; 

     System.out.println("Fido says " + theAnimals[0].makeSound()); 
     System.out.println("Fluffy says " + theAnimals[1].makeSound()); 

     // We can also pass subclasses of Animal and they just work 
     speakAnimal(fluffy); 

    } 

} 

我看到一些其他的答案这里阅读，我不得不添加进口java.util.Scanner的;

，我已经有..

请告诉我问题的代码... 谢谢！

Answer 1

的问题是从错误信息清晰 -

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    Syntax error, 'for each' statements are only available if source level is 1.5 or greater 

你需要Java 1.5或更高版本，可以从here

---

下载最新版本的Java JDK中的或者你可以做最终的说，并让你的循环兼容较低版本的Java（虽然我会建议升级到1.5以上，1.5就像非常非常旧的版本）。

Answer 2

行for(String word : stringArray)是所谓的“for each”循环 - 在Java 1.5中增加了一个便利。

但似乎你的编译器配置在1.5以下，所以它不支持每个循环。

所以，你可以：

• 改变编译器级别

• 变化循环为1.4兼容

  String[] stringArray = {"Random", "Words", "Here"}; 
  String word; 
  for(int i = 0; i < stringArray.length; i++) 
  { 
      word = stringArray[i]; 
      System.out.println(word); 
  } 
  

  （其实这是编译器会为你做...）