考虑到这段代码,我能绝对确定finally块总是执行的吗,不管something()是什么?
try {
something();
return success;
}
catch (Exception e) {
return failure;
}
finally {
System.out.println("I don't know if this will get printed out");
}
考虑到这段代码,我能绝对确定finally块总是执行的吗,不管something()是什么?
try {
something();
return success;
}
catch (Exception e) {
return failure;
}
finally {
System.out.println("I don't know if this will get printed out");
}
当前回答
此外,finally的返回将丢弃任何异常。http://jamesjava.blogspot.com/2006/03/dont-return-in-finally-clause.html
其他回答
Finally is always run这就是重点,只是因为它出现在返回后的代码中并不意味着它就是这样实现的。Java运行时有责任在退出try块时运行此代码。
例如,如果您有以下内容:
int foo() {
try {
return 42;
}
finally {
System.out.println("done");
}
}
运行时将生成如下内容:
int foo() {
int ret = 42;
System.out.println("done");
return 42;
}
如果抛出未捕获的异常,finally块将运行,异常将继续传播。
除非由于JVM崩溃或调用System.exit(0)而导致程序异常终止,否则finally块将始终执行。
除此之外,finally块中返回的任何值都将覆盖finally块执行之前返回的值,因此在使用try finally时,请注意检查所有退出点。
试用间苯二酚示例
static class IamAutoCloseable implements AutoCloseable {
private final String name;
IamAutoCloseable(String name) {
this.name = name;
}
public void close() {
System.out.println(name);
}
}
@Test
public void withResourceFinally() {
try (IamAutoCloseable closeable1 = new IamAutoCloseable("closeable1");
IamAutoCloseable closeable2 = new IamAutoCloseable("closeable2")) {
System.out.println("try");
} finally {
System.out.println("finally");
}
}
测试输出:
try
closeable2
closeable1
finally
是的,它将始终调用,但在一种情况下,当您使用System.exit()时,它不会调用
try{
//risky code
}catch(Exception e){
//exception handling code
}
finally(){
//It always execute but before this block if there is any statement like System.exit(0); then this block not execute.
}
此外,finally的返回将丢弃任何异常。http://jamesjava.blogspot.com/2006/03/dont-return-in-finally-clause.html