为什么android studio不总是警告抛出异常的调用方法？

Question

In some cases, android studio lets me call a method which throws an exception, without a try/catch. Why is that? How can I enforce it to always warn me about it?

Answer 1

Two kinds of exceptions

Checked Exceptions are those that are inherited from the Exception class, you will be warned

Unchecked Exceptions are inherited from RuntimeException , calling a method that throws them will never show a compiler warning, but as the name suggest "just" mess it up at runtime ;-)

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Here a short list of common exceptions, to help you weary restless searching fellows out ...

UNCHECKED exceptions

• StackOverflowError
• RuntimeException
• ArrayIndexOutOfBoundsException
• ClassCastException
• IllegalArgumentException
• IllegalStateException
• NullPointerException
• NumberFormatException
• AssertionError
• ExceptionInInitializerError
• NoClassDefFoundError

CHECKED exceptions

• Exception
• ClassNotFoundException
• CloneNotSupportedException
• FileNotFoundException
• ParseException
• InstantiationException
• InterruptedException
• IOException
• NoSuchFieldException
• NoSuchMethodException

Answer 2

The problem seems to be about checked/unchecked Exceptions, as @RubioRic and @Altoyyr said. I didn't know about the difference.

Answer 3

For the exception you can handle, use

try{
    //your business logic
}catch(Exception e) {
    //Err handling logic
}

For the exception you cannot handle, do not use an empty try/catch block, but use throws exception instead. Let the custom error handler you wrote to handle it from outer class etc.

//business logic which you know it will throw certain kind of exception
throw XException("your err descrption");

The last case is you don't even know what happened, please fix the code according to the exception/ err trace, it is a bug where business logic should handle well.

Please read about the error handling in java throught this link: http://www.onjava.com/pub/a/onjava/2003/11/19/exceptions.html