jsp一些异常总结（转自校内--2008-11-26 20:01 (分类:默认分类)）

一些异常的总结（不断的总结，加入）

java.lang.ClassCastException: java.lang.String
java.lang.Object
   |
   +----java.lang.Throwable
           |
           +----java.lang.Exception
                   |
                   +----java.lang.RuntimeException
                           |
                           +----java.lang.ClassCastException

public class ClassCastException extends RuntimeException
Thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance. For example, the following code generates a ClassCastException:
     Object x = new Integer(0);
     System.out.println((String)x);
     ClassCastException()

Object o="l am a student";
String s=(String)o;
System.out.println(s);

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 14
 at java.lang.String.getChars(Unknown Source)
 at java.io.BufferedWriter.write(Unknown Source)
 at package1.file2.main

BufferedWriter output=new BufferedWriter(new FileWriter("D:\\bb.txt"));
String line ;
output.write("pan jun", 0, 14);
output.close();
这里的异常是应为长度超过了7，如果小于七是没问题的

还有就是一定要output.close(),否则就不能写进去了
java.lang.UnsupportedClassVersionError
Exception in thread "main" java.lang.UnsupportedClassVersionError: Math (Unsuppo
rted major.minor version 50.0)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass
你编译和执行用了不同的jdk版本
你可以看看你的path中java是在什么地方，使用相同的版本就好了