UnsupportedOperationException往往发生在对由数组转换而成的list的操作中。
例如：
public class ListTest {
public static void main(String[] args) {
String[] array = {"1","2","3","4","5"};
List<String> list = Arrays.asList(array);
list.add("6");
}
}
执行结果：
Exception in thread "main" java.lang.UnsupportedOperationException
at java.util.AbstractList.add(AbstractList.java:148)
at java.util.AbstractList.add(AbstractList.java:108)
at com.atguigu.test.ListTest.main(ListTest.java:11)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
发生的原因如下：
调用Arrays.asList()产生的list的add、remove方法时，编译器会发现Arrays.asList()返回的是Arrays的内部类，而不是java.util.ArrayList.虽然它两都是集成AbstractList，但是remove、add等方法在AbstractList中是默认throw UnsupportedOperationException的。
解决方案：
public class ListTest {
public static void main(String[] args) {
String[] array = {"1","2","3","4","5"};
List<String> list = Arrays.asList(array);
List arrList = new ArrayList(list);
arrList.add("6");
}
}
