The way to compare with null is to use x == null and x != null . Moreover, x.field and x.method() throws NullPointerException if x == null . ... <看更多>

It is common to want to check an object against null , but this should not be done using the Equals method. If the object really is null ... ... <看更多>

operators to check if an object reference is null or not. ... 10K views 3 years ago Java Fundamentals And Internal Mechanism. Show less. ... <看更多>

Java code link: Is the Apex Runtime not throwing a null ptr exception in Apex a bug or undocumented feature? apex · null-pointer ... ... <看更多>

Because the get(Object) method of the Map interface can return null , you need to add code to check whether the return value is null or not, that is, a null ... ... <看更多>