I'm working in Java.
I commonly setup some objects as such:
public class Foo {
private SomeObject someName;
// do stuff
public void someMethod() {
if (this.someName != null) {
// do some stuff
}
}
}
The question is: Is someName
in this example equated to null
, as-in I can reliably for all objects
assume null-checking uninitialized objects will be accurate?
Correct, both static and instance members of reference type not explicitly initialized are set to null
by Java. The same rule applies to array members.
From the Java Language Specification, section 4.12.5:
Initial Values of Variables
Every variable in a program must have a value before its value is used:
Each class variable, instance variable, or array component is initialized with a default value when it is created
[...] For all reference types, the default value is
null
.
Note that the above rule excludes local variables: they must be initialized explicitly, otherwise the program will not compile.