Think in Java Notes _chapter12_1_exception Basics _ Inheritance and runtimeexception processing 1

Exceptions in Java

2. Exception exception we can deal with, can be remedied, encountered an exception will not be executed?

   1. Package cn.seven.shengsiyuan.exception;/* * time:2015 April 05 12:24:58, Ching Ming Festival * location:501 *  */public class ExceptionDemo1 {public static void main (string[] args) {//TODO auto-generated method Stubint A = 3;int b = 0;int C = A/ b;//This sentence execution will occur an exception, the following statement will not execute SYSTEM.OUT.PRINTLN ("------"); System.out.println (c);}}
      
      /*
      Exception in thread "main" java.lang.ArithmeticException:/By zero
      At Cn.seven.shengsiyuan.exception.ExceptionDemo1.main (exceptiondemo1.java:17)
      
      */

4. Exceptions in the exception inheritance system-java inherit from the exception class exception into two main categories:
   Checked Exception (non-runtime exception)
   Unchecked Exception (runtime exception runtime Exception)
   
   

   Java.langclass throwable    java.lang.Object        java.lang.Throwable all    implemented Interfaces:        Serializable    Direct known subclasses:        

   
   

   Java.langclass Exception    java.lang.Object        java.lang.Throwable            java.lang.Exception

2. 1. Run-time Exception runtimeexception

          Java.lang.Object        java.lang.throwable-            java.lang.Exception                java.lang.RuntimeException                    Javax.management.JMRuntimeException

   2. Non-runtime exception: inherits the exception class, but does not inherit exceptions from the RuntimeException class
3. RuntimeException exception handling-fixed processes and patterns
   2. Try{}catch (Exception e) {}

   4. Package cn.seven.shengsiyuan.exception;/* * time:2015 April 05 12:24:58, Ching Ming Festival * location:501 *  */public class ExceptionDemo1 {public static void main (string[] args) {//TODO auto-generated method Stubint c = 0;try{int A = 3;int B = 2; C= A/b; SYSTEM.OUT.PRINTLN ("---hello---");} catch (ArithmeticException e) {//assigns the exception object generated by 19 rows to Ee.printstacktrace ();//printstacktrace printing exception information from the Throwable class method} Finally{system.out.println ("finally");} SYSTEM.OUT.PRINTLN ("------"); System.out.println (c);}} /* * 19 rows with an exception, resulting in an object for the exception class ArithmeticException * When an exception occurs, enter the catch block, take over by the catch, and then execute the contents of the Catch block * execution is complete, then execute the SYSO statement *  *  * The focus now is on the 21-row-catch statement process */

   6. Complete exception-handling structure

      try{//the code block of a statement that may have an exception}catch (Exception object) {//For processing after an exception occurs}finally{//the statement that will eventually be executed regardless of whether an exception occurred, preventing some statements from being executed because an exception occurred}

      Package cn.seven.shengsiyuan.exception;/* * time:2015 April 05 12:24:58, Ching Ming Festival * location:501 *  */public class ExceptionDemo1 {public static void main (string[] args) {//TODO auto-generated method Stubint c = 0;try{int A = 3;int B = 0; C= A/b; SYSTEM.OUT.PRINTLN ("---hello---");} catch (ArithmeticException e) {e.printstacktrace ();//printstacktrace printing exception information, methods from the Throwable class}finally{ System.out.println ("finally");//must be executed regardless of whether an exception occurred}//system.out.println (c); The question is why is c=0 still output here? Because of c=a/b; statement exception, C no assignment statement}}

5. If there are multiple exceptions in the program, only specific exceptions will be handled by the particular catch.

Think in Java Notes _chapter12_1_exception Basics _ Inheritance and runtimeexception processing 1