The null pointer exception problem is mostly an error in integer automatic unpacking
Error code:
Integer a=null;
if(a==1||a==null){
System.out.println("111");
}
error reporting: java.lang.nullpointerexception
Error reporting reason:
Integer object is null. In the process of automatic unpacking, obj.xxxvalue will throw NullPointerException
Problem solving:
If you want to continue the multi conditional judgment, you should put the judgment empty in the first place
Modification code:
Integer a=null;
if(a==null||a==1){
System.out.println("111");
}
To avoid another null pointer like exception error, you need to master the knowledge of null in Java. You can refer to another article What you should know about null in Java