Introduction to using preconditions to check incoming parameters in Java

Preconditions is a class library in guava, which is used to check the incoming parameters. A common usage is as follows:

The usage is simple and clear, that is, check whether the parameter elements is null. If it is null, throw a NullPointerException. Of course, there are other methods in the preconditions class, which may meet the inspection of almost all incoming parameters. The advantage of preconditions is that it is easier to understand in call stack, and each method also provides variants of formatted strings, such as: