如何在Java中静态检查null指针异常？

Question

There are some NullPointerException crashes in my Android project. How can I static check or test the NullPointerException crash in Java / Android?

Answer 1

The correct way to avoid a nullPointerException at runtime is to surround your piece of code in a null check like this:

if (mySomething != null) {
    doSomething(mySomething);
}

This will only use mySomething if it is not null and can be used, thereby avoiding nullPointerException s. You can also catch a nullPointerExcepton , but this is not a good idea.

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You can also use a static analysis tool like FindBugs or IntelliJ's built in inspections to analyze your code and tell you if it could produce a nullPointerException .

Answer 2

There is a great article which describes best practices for the most common cases of NPE: http://javarevisited.blogspot.hu/2013/05/ava-tips-and-best-practices-to-avoid-nullpointerexception-program-application.html

You could parametrize your code analyzer tool to catch these cases.