已检查和未检查异常详解-Java快速入门教程

package exceptionHandling; 
public class CheckedExceptionEx1 
{ 
public static void main(String[] args) 
{ 
 System.out.println("Hello Java"); 
 Thread.sleep(1000); // Here, main thread paused for a specified amount of time. // Compilation error. 
 } 
}

Output: 
      Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
      Unhandled exception type InterruptedException

public class CheckedExceptionEx1 
{ 
public static void main(String[] args) 
{ 
   System.out.println("Hello Java"); 
// Apply the try-catch block to handle checked exception.
   try 
   { 
     Thread.sleep(1000); 
   } 
   catch(InterruptedException e) 
   { 
     e.printStackTrace(); 
    } 
 } 
}

Output: 
       Hello Java

package exceptionHandling; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
public class CheckedExceptionEx 
{ 
public static void main(String[] args) throws FileNotFoundException 
{ 
 File file = new File("not_existing_file.txt"); 
 FileInputStream stream = new FileInputStream(file); 
 } 
}

Output: 
       Exception in thread "main" java.io.FileNotFoundException: not_existing_file.txt 
       (The system cannot find the file specified)

public class UncheckedExceptionEx1 { 
public static void main(String[ ] args) 
{ 
 int x = 10; 
 int y = 0; 
 int z = x/y; // runtime exception.
 System.out.println(z); 
 } 
}

Output: 
   Exception in thread "main" java.lang.ArithmeticException: / by zero 
   at exceptionHandling.UncheckedExceptionEx1.main(UncheckedExceptionEx1.java:9)

public class HandleRuntimeException {
public static void main(String[] args) 
{
  int x = 10; 
  int y = 0; 
// Apply try-catch block to handle runtime exception.
  try {
    int z = x/y; // runtime exception.
    System.out.println(z);
  } catch(ArithmeticException ae) {
       System.out.println("A number cannot be divided by zero");
    }
  }
}

Output:
      A number cannot be divided by zero

public class UncheckedExceptionEx2 { 
public static void main(String[] args) 
{ 
   int x[ ] = {1, 2, 3, 4}; 
/* Here, an array contains only 4 elements, but we will try to * display the value of 6th element. 
   It should throw * ArrayIndexOutOfBoundsException */ 
   System.out.println(x[6]); 
 } 
}

Output: 
      Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6

public class UncheckedExceptionEx2 { 
public static void main(String[] args) 
{ 
 try 
 { 
   int x[ ] = {1, 2, 3, 4}; 
   System.out.println(x[6]); 
 } 
 catch(ArrayIndexOutOfBoundsException e)
 { 
   System.out.println("Specified index does not exist. " + "Please correct the error."); 
  } 
 }
}

Output: 
       Specified index does not exist. Please, correct the error.