java学习（23）_运行时异常总结

红太狼 2022-06-11 00:10 120阅读 0赞

**java学习（23）\_运行时异常总结（待完善。。）**

**运行时异常：运行时异常都是RuntimeException的子类**

> **1. NullPointerException    空指针异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		String s= null;
>     		System.out.println(s.charAt(0));
>     	}
>     }
> 
> ![Center][]  
>   
> 
> 
> **2. ArithmeticException  数学异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		System.out.println(1/0);
>     	}
>     }
> 
> ![Center 1][]  
>   
> 
> 
> **3.ClassCastException  类型转换异常**
> 
> **示例：**
> 
>     class A{}
>     class B extends A{}
>     public class Test01 {
>     	public static void main(String[] args) {
>     		A a = new A();
>     		B b = (B) a;
>     		
>     	}
>     }
> 
> ![Center 2][]  
>   
> 
> 
> **4.ArrayIndexOutOfBoundsException 数组下标越界异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		int[] a = new int[2];
>     		System.out.println(a[4]);
>     	}
>     }
> 
> ![Center 3][]  
>   
> 
> 
> **5.StringIndexOutOfBoundsException 字符串下标越界**

> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		String s = "abc";
>     		System.out.println(s.charAt(5));
>     	}
>     }
> 
> ![Center 4][]  
>   
> 
> 
> **6.IndexOutOfBoundsException  下标越界异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		ArrayList<Integer> list = new ArrayList<Integer>();
>     		list.add(1);
>     		System.out.println(list.get(3));
>     	}
>     }
> 
> ![Center 5][]  
>   
> 
> 
> **7.NumberFormatException 数字格式化异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		System.out.println(Integer.parseInt("1a2"));
>     	}
>     }
> 
> ![Center 6][]  
>   
> 
> 
> **8.InputMismatchException  输入不匹配异常**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		Scanner sc = new Scanner(System.in);
>     		System.out.println("请输入一个整数：");
>     		int a = sc.nextInt();
>     	}
>     }
> 
> ![Center 7][]  
>   
> 
> 
> **9.ArrayStoreException  数组协变异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		String[] s = new String[3];
>     		Object[] o =s;
>     		o[1] = 1;
>     	}
>     }
> 
> ![Center 8][]  
>   
> 
> 
> **10.ConcurrentModificationException   快速报错异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		List list = new ArrayList(Arrays.asList(1,2,3));
>     		Iterator it = list.iterator();
>     		while(it.hasNext()){
>     			System.out.println(it.next());
>     			list.add(4);
>     		}	
>     	}
>     }
> 
> ![Center 9][]  
>   
> 
> 
> **11.UnsupportedOperationException  不支持该操作异常**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		List list = Arrays.asList(1,2,3);
>     		list.add(4);
>     	}
>     }
> 
> ![Center 10][]  
>   
> 
> 
> **12.NoSuchElementException    没有这么一个元素异常**
> 
> **示例：**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		List list = Arrays.asList(1,2,3);
>     		Iterator it = list.iterator();
>     		System.out.println(it.next());
>     		System.out.println(it.next());
>     		System.out.println(it.next());
>     		System.out.println(it.next());
>     	}
>     }
> 
> ![Center 11][]  
>   
> 
> 
> **13.IllegealMonitorStateException  非法监听器状态**
> 
> **示例：**
> 
>     class A implements Runnable{
>     	Object obj;
>     	public A(Object obj){
>     		this.obj = obj;
>     	}
>     	@Override
>     	public void run() {
>     		while(true){
>     			synchronized (obj) {
>     				System.out.println("1234");	
>     				try {
>     					obj.notify();
>     					obj.wait();
>     				} catch (InterruptedException e) {
>     					// TODO Auto-generated catch block
>     					e.printStackTrace();
>     				}
>     			}
>     		}
>     	}
>     	
>     }
>     class B implements Runnable{
>     	Object obj;
>     	public B(Object obj){
>     		this.obj = obj;
>     	}
>     	@Override
>     	public void run() {
>     		while(true){
>     			synchronized (obj) {
>     				System.out.println("abcd");	
>     				
>     			}
>     			try {
>     				obj.notify();
>     				obj.wait();
>     			} catch (InterruptedException e) {
>     				// TODO Auto-generated catch block
>     				e.printStackTrace();
>     			}
>     		}
>     	}
>     	
>     }
>     
>     public class Test01 {
>     	public static void main(String[] args) {
>     		Object obj = new Object();
>     		Thread t1 = new Thread(new A(obj));
>     		Thread t2 = new Thread(new B(obj));
>     		t1.start();
>     		t2.start();
>     	}
>     }
> 
> ![Center 12][]  
> 
> 
>   
> 
> 
> **14.****EmptyStackException 空栈异常**
> 
>     public class Test01 {
>     	public static void main(String[] args) {
>     		Stack s = new Stack();
>     		s.push(1);
>     		s.pop();
>     		s.pop();
>     	}
>     }
> 
> ![Center 13][]  
>   
>

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